I got some questions regarding your sorcerer spell selection as I'd like to try a Sage Sorcerer. Not quite as strong as Sylvan but I like the concept.

So far my spell planning goes like this:

lvl 1: Mage Armor, Grease, Magic Missile*, Enlarge Person, True Strike, Reduce Person
lvl 2: Glitterdust, Burning Arc, Invisibility*, Mirror Image, Blur, X
lvl 3: Stinking Cloud, Haste, Dispel Magic*, Battering Blast, Resist Energy Communal
lvl 4: Animate Dead, Greater Invisibility**, Dimension Door*, Enervation, Protection From Energy Communal, X
lvl 5: Icy Prison, Phatasmal Web, Break Enchantment*, Acidic Spray, X
lvl 6: Chains of Light, Sirocco**, True Seeing*, Chain Lightning, Cold Ice Strike
lvl 7: Legendary Proportions, Waves of Exhaustion, Banishment*, Firebrand
lvl 8: Stormbolts, Rift of Ruin**, Power Word Stun*, Mind Blank, X
lvl 9: Mass Icy Prison, Tsunami, Clashing Rocks*

* Bloodline Spells
** Spells Picked with New Arcana

Feats as usual: Spell Foci for Conjuration/Evocation, Precise Shot, Improved Initiative, some Spell Penetration, some Metamagic.

Some things that differ from your proposed sorcerer spells:
Burning Arc at level 2 seems to do more damage then Scorching Ray. But I'm not sure about that. Battering Blast works very nicely with pit spells. Enervation seems very good vs certain BBEGs.Phantasmal Web is a very nice no friendly fire control.

What's your opinion on this spell selection?

Another question:
Why do you think Wizards are shitty sorcs? Getting Haste and Stinking cloud at level 5 seems huge. Faster spell progression in general is quite good, especially since sorcs only get a single spell when they reach a new level. They can easily switch spells so they can stay on the newest pit spell etc.Just choose Enchantment and Divination for opposition schools, they don't have decent spells anyway.

Thanks in advance for input on those matters!

for sage you really don't want to be an evoker. Focus on necro instead(illusion is also fine, necro is just more universal) with conjuration as a secondary school cause you don't need insane DC for stinking clouds to be awesome. At least you get empowered(with a rod) circles/banshee for somewhat decent damage. Better than evoker can get anyways. Evo in general is the worst school of magic in the game unless you stack dice and damage per dice, then it's suddenly the best one.

As to wizards... 1 level is not that much and if we weigh in the pet of sylvan merc it's a no-brainer. There is also animate dead to abuse once MC dings 5(by grabbing tristian bit late) so level 5 is not even a concern(and it'll happen about half a level before merc has 5 too). It's everything before that might be problematic. One kinda ok-ish thing wizards have is their metamagic is standard action instead of full action for sorcs... Except sorcs don't really need metamagic and rods don't count. The problem is you don't ever use versatility of the wizard in this game, so instead of having variety, you will actually have less spells to choose from. Lets say you are a conjueror of some stripe. Your level 3 will literally be filled with hastes and stinking clouds. That's it. You just won't keep something that's situationally useful in your book. And that's how it goes for the wizard. It's not pnp where wizard is a godsend with a bag of tools for every occasion. And spell progression... it really doesn't matter. Caster's job is to control the battlefield first and foremost and that's done with heightened stinking clouds/grease/slow/web/whatever else and what all those spells have in common is them being low-level. Only place where wizard 1 level is really valuable would be in some heavy multi-class scenarios where it can give you another spell level access. I guess divination passive is also decent enough, but not something that'd sell wizards to me. As to opposition schools you are better off tossing necro+evocation in case of wizards and pick divination as primary cause the bonus is pretty good. Enchantment has greater heroism you don't wanna miss even if you have a bard and divination has sense vitals and a few other decent spells(especially for a wizard. Might as well put some of that versatility to use on high level spells).

Scorching ray is 4d6 x3 +5d6 sense vitals. Pretty good. Due to the ray nature of the spell you get 3 chances to do 9d6 with no save and additional hits/crits are just a net benefit. Battering and all bull rush things allow ENEMIES to make opportunity attacks against all your units in their path. It's literally awful. Enervation is ok, but really it's kinda meh. If your party is stacked enough things just don't live long enough to stack negative levels. And by don't live long enough I mean they are being one-shot for the most part. Web is pretty decent.

The game is not about efficiency. The game is about fun. So long as you like what you are doing it's perfectly fine. And for hard it's enough for every build to just make some good sense. Synergy can be easily left behind.

Feats are interesting in a way that it's easy to overvalue them. In practice there are only so many of those that really are needed. Whereas some class talents cant be replicated. Same with BAB and saves. People pay way too much attention to those and respect them more than they are worth for no good reason.

Interesting! Thanks for your input!

Why the dislike of evocation? Icy Prison has been incredibly powerful for me. Sirocco is also quite good but wants to be combined with other crowd control. Stormbolts seems like a great double threat. Many of those evocation spells are my favorite Spells for their level. I didn't know that bit about Battering Blast, that would be really, really bad (will test tomorrow).

I don't see many good necro spell asking for a save. Circle of Death is decent, but also costly. Rolling the dice on creatures affected is another downer. Waves of Exhaustion is no save. Plague Storm seems bad. Finger of Death targets Fortitude and has a short range. Banshee Blast has a good effect but the small cone is a big let down. Eyebite is just bad.

For illusion I see mostly two save spells. Phantasmal Web is really the only good offensive illusion spell, or did I miss something?

Transmutation has some really nice spells in there: Slow, Obsidian Flow, Tar Pit. I can certainly see getting greater spell focus for those. But since I really only have room for spell focus in two schools, I'm not sure what to ditch.

How do you stack dice and damage per die? Does the Sylvan Sorc has something like that?

Evo without crutches is just not enough damage. Your stormbolts will top out at 300 damage with grandmaster rod and full kit of damage/dice gear, which is pretty pathetic for all the investments needed. What you want to be doing is removing threats with your spell slots. So whole encounter must be either controlled by spending a slot or two. Or one-shotted. There is nothing wrong with running a sage, wizard or whatever else, but Evo is patently useless for them as stormbolts is the best case scenario for an evo user and even that's not impressive without AT. Everything else will be much worse.

What you do as a necro sage is start as a conjueror with par for the course stinking cloud spam and right when you get your class focus you get undeath to death and circle of death. Both are handy exactly by the time you get em. Then you also get banshee for 300 damage with empower rod(which is the best damage you can hope for without AT) and horrid is pretty much the same as stormbolts for him. Rest is whatever, but then again you don't need a lot. You just want some decent damage spells to go nova with rods if/when you need to.

Illusion has both decent control and Weird. The latter is any encounter with living targets done in one cast if you stack DC high enough, which is exactly what is required from late-game arcane caster.

Transmutation spells are nice, but everything but slow is pure aids to use. Vanilla game has no option to dismiss spells and there is no easy way of making transmutation party-friendly even if you mod dismissal in, so it only leaves slow as a usable option and slowed enemies are not fully disabled, so it's kinda meh.

See AT/Sorc.
https://i.imgur.com/iYQxQqn.png
https://i.imgur.com/I5K6uRo.png
That's how nuker sorc does.
But that's a late-game thing. That's pretty much why casters are better off as mercs(apart from the fact they don't need moire than 20PB), so you can run sylvan conjueror/necro till MC20 and all the bells and whistles required for it and then swap to AT sorc.
Basically what you do is stacking dice and then stack +1 damage per dice rolled things(and yes, sneak dice totally count). Since there is a rod of flaming vengeance in the game that converts everything to fire we can roll a fire dragon sorc for +1, and use attire of arcane annihilation for another +1. Technically, there is an amulet with another +1 if I wanted to push stormbolts over 400 damage, which is not needed even for unfair, so I opt to use dying wisdom instead.
So that makes me being able to use sotrmbolts and then to use quickened chain lightning for about 500-650 aoe damage per round, cause rods are busted in this game. Nobody really needs metamagic outside of heighten for control spells.
I've done it on my solo unfair run as a sylvan8/V1/SF1/AT10 just cause I needed a pet to solve early-game, so it's surely doable on sylvan, but it's degenerate solo things, not how it's done in the party. Didn't make the challenge any more fun, but that's the easiest thing to solo the game I could think of.

I'm not suggesting Evocation for damage, I'm suggesting Evocation for control.

Dex is traditionally the best save to target in Pathfinder. Evocation has the only higher level dex targeting control in the game. The damage is just a kicker, although 300 AoE damage isn't too shabby imho.

It's 300 with grandmaster rod and 2 +damage/dice items, while banshee only needs greater empower rod, which are rather plentiful, so you get that and can grandmaster your horrid instead for the same resulting damage. And CC in evo is pretty medoicre, if we are being generous. Level 9 spell for simple mass disable that low-level spells do admirably? Sirocco is ok, but it's not party-friendly and there is no way to make it such. Firebrand/immunities and all do not help against knockdown. And saves you target really don't matter. Just stack the numbers higher and don't use save or suck for CC. Endgame enemies have +30 will. Take a guess if it affects weird at all with 50-ish DC you can have. Not to mention there is a better level1 reflex spell than icy prison: Grease. No SR allowed and no chance to fail cause of the sheer amount of saves forced(all duration spells like that are slightly bugged and force 2 checks on 1st round in this game on top of being more reliable as is). Oh and everything and it's dog is immune to ice. I don't use icy prison pretty much ever so don't rememer off the top of my head if CC cares about immunity, but there's that. And. if anything, targeting weak save is exactly what arcane/sage are geared to not care about. Kinda the whole point of the class is to be sort of a one trick pony casting weird on +30will targets as prime example.

Mind you I aint telling you not to play what you want to. I am just making sure you understand what you are getting and what you could be getting. If you feel evo sage will be fun - go for it, obviously.

Hi InEffect, did you ever post your Tristian summoner build anywhere?

@ineffect : thanks for all your advice and builds. Been following this topic for a long time, helps a lot !

Also, a question : do you think it's possible to build a party without a cleric by relying on the bard (valerie) and alchemist (jubi) for the defensive spells like delay poison, freedom, resist energy, death ward and heal ?

If not, how would you build a cleric that's more than a buff bot (like Harrim and Tristian are ...) but can fulfill at least two roles ? Like divine magic + control or divine magic + tanking ?

I guess a control cleric mean he'll have to follow Gozreh or Pharasma for the water domain. Gozreh seems better since it will open the plant domain (for mind blank) or the animal domain (if we want a pet ... which I don't). However, the DC of his control spell would always be lower than a Sage sorcerer due to the lack of "school power" and the +4 int staff... so not sure if it's worth it. Also, we can't pick the community domain ...

Regarding the "cleric tank" I'm not too sure how to build one. I guess high wisdom and dex + monk dip would be the way to go but it may still be not enough to obtain a decent AC. We could go Erastil for the community domain if the idea is to go for high wisdom ? Yeah ...not sure how to solve the "cleric tank" problem without deeping too much in other class and loosing spell progression and access to high level spell ... having low DPR wouldn't be an issue I guess (since he'll be already fulfilling 2 roles).

Any suggestion ?

Thanks !

Yes. Most things cleric brings to the table can be replicated by other classes and liberal scroll usage. Main reason to bring cleric onboard is animate dead at level5 and archons aura. That and guarded hearth with maxed out wis is insane.

Ecc8/Wiz3/Theurge9 abadar nobility/travel will have everything eventually(meaning control and divine support). Level cler8 before wizard. Only problem is he gets online by mid-teens. Before that - you can't have everything. Or erastil community+something for guarded health. Whatever you fancy.

Gozreh is fine, but he doesn't bring anything unique to the table. As to the DC's... you don't need it sky high for stuff like stinking cloud. Spare him amulet of dying wisdom and vivi2 for cognatogen if you want more. The whole deal with clouds and the lot of over-time effects is that you can have just reasonably stacked DC and rely on the sheer amount of checks forced.

Cleric tank can be alright... if you don't play on unfair. Just do STR staff ecc17/M1/something 2 and it'll be ok-ish(otherwise you just won't have any damage) and clerics are actually decent enough at pushing STR. It's usable on unfair as well, but I don't like reloading and 2.5% to be hit is annoyingly high.
Nah. I decided it's not worth the effort. Animate dead and elemental swarm are better than generic summon spells anyways and they don't benefit from summoning feats.

The effort to write? Or the viability of playing it? Because don't you literally just swap 3-4 feats and leave the rest the same basically?

All of the above, really. What feats tristian has matters little in practical application as most of his slots will go to animate dead, buffs and out of combat heals anyways. And evo foci give more cause they at least apply to archon's aura, which is always on for every cleric ever.

Thanks for your input!
I love theory crafting and wanted an informed opinion, that's why I asked :)

Icy Prison has some advantages over Grease, mainly not friendly firing. But I do see your point. Especially with monsters happily running happily into AoEs, they are very strong in this game.

I never really did the counting for DCs, I just saw some saves and assumed the rule of PnP is still true: Fort>Wis>Dex for monsters.

Sorcerers have always been exceptionally good one trick ponies. I totally see that being effective in PF:KM, but I think diversity is more fun.

It's not like you are really-really a otp. It's actually the opposite in some sense. It's just Instead of choosing by save sage sorc chooses by template and effect. And due to how they work over time effects like grease and clouds don't give rats behind about saves so long as those are decently stacked. See unfair guide for sylvan sorc spell list for necro+conjueror. Can do even better with illusionist+conjueror sage if you only care about CC and one-shots.

ps. speaking of saves it's wis early-game, reflex mi-dgame, fort late-game for the lowest save on most common mobs, not that it matters.