Observation: Different classes have different power curves.

For example, if we assume that the class's main skills are used (typically, but not always, the primary skill), we see:
* Priest: Gets some useful spells early, which is the big advantage here. A battle priest's combat effectiveness falls off in the lower teens, just like the magic abilities of many casters, but picks back up later. This class can be said to peak late-game, with access to a nuke, albeit the weakest one, more HP and better equipment than the other specialists (and more HP than a bishop), and the ability to use The Mauler. Both mace and staff are weak for a while, but then get sudden boosts, with staff getting it first.
* Lord: Like Priest (with mace) in terms of weapons, but dual wielding gives this class more power in the endgame, when the strongest offhand weapon is a mace, and there's a strong buyable main-hand mace. Probably weaker than other fighter-types until then, but ends up strong at endgame, with the peak coming when you reach Ferro and can buy The Mauler. Spellcasting still has room to improve. Worth noting that, with the route I like to take, the Lord gets some major offensive boosts in the mid teens, a point where many classes stagnate.
* Valkyire: Unlike Priest and Lord, the Valkyrie's main weapon type, Spears, gets constant good options early. As a result, physically the Valkyrie peaks early, with the Str/Dex Valkyrie getting the extra attack (and the extra swing with some weapons) in the late single digits; Str/Int will need to wait a bit longer, but will get better magic capabilities in the late game. allowing for a smoother growth curve throughout the game. Might still stagnate in the teens, but does so at a higher power level than full casters or experts. Also less effective than other physical builds endgame (unless you go Mook), but still ends up being effective at that point.
* Bard/Gadgeteer: These two classes really fall off offensively as you get through the teens, and are just not that good at magic offense as you approach level 18. In particular, at level 17 their magic offense is quite terrible. They do at least get decent physical attacks, and their power has a discontinuity at level 18 (or whenever you get the items that require level 18, whichever comes second), so they're good in the endgame. Also, they can party heal with just the cost of stamina once they reach level 11, which gives them a good use in the teens, even if their magic offense falls off hard in those levels.

I disagree. The basic classes do quite well in this game, enough to rival the hybrids and elites. The point proven is that they can get 4 attributes maxed by level 30.
My Psionic and Mage are maxing out Close Combat and Staff and Wand skills. They will be good at melee, as well as the others (this is the disease of perfection).

The more basic classes may be better at their one thing than hybrids, but the thing is that hybrids are good enough, and they can fill multiple roles (and a hybrid is going to be better at fighting than a specialist caster).

Your Psionic and Mage aren't going to be as good at melee as a Monk and Samurai would be (but will be better casters, and may still be good enough at melee).

My point with the Bard and Gadgeteer is specific to their magic damage capabilities, and specific to that level range; at level 17 they're horrible for magic damage, but at level 18, provided you have the right items, they're good at that again

There's always trade-offs when choosing a class in this game.

Also, I'd argue that, except in special cases like solo runs, anything past 25 doesn't really matter.

I agree with you that "anything past 25 doesn't really matter". I'm just trying to create a MDP that can do magic damage first (what they do best), combined with the best melee and ranged attacks that they can handle (obviously worse than tougher characters).
The Staves of Doom allow even the Alchemist, Psionic, and Mage to do healthy melee damage to enemies, obviously not able to compete with hybrids. But that's not what they're trying to do.
The MDP I created is trying to kill low-level, high HP enemies with kill-all spells in round 1, and more manageable enemies with lower HPs and a similar level with magic spells.
I'm training the Psionic and Mage with Quarterstaves, just because. There isn't any reason not to, especially with boss enemies like El Dorado, Nessie, Al-Sedexus, and the Dark Savant.

The way I see it, when suitably built, a full caster will be better at melee than a hybrid will be at spellcasting.

In other words, a Str/Int Valkyrie will not be able to cast spells as well as a Str/Int Priest can fight in melee.

Of course, there are caveats. In particular, there's a middle section of the game where the hybrid will be significantly better at fighting, for a few reasons:
* It takes a long time for a full caster to get a second attack and a second swing. During this time, a hybrid may have 2-4 times as many attacks as a full caster.
* Equipment limitations come into play. There's only one reliably obtainable Staff of Doom, which is the easiest strong weapon to get that a full caster can equip, whereas you can buy multiples of the good polearms. For mace users (Priest/Bishop), there's only one Diamond Eyes, and it might be tricky to obtain until you've gained some levels, though the Annointed Flail (3-10 damage, x2 against undead) can help in that particular fight.

But once you reach the mid-to-late teens, a full caster can end up with the second attack and/or swing, though they might need magical aid (haste/superman) to get it, especially at first.

Sure, hybrids are more powerful than full casters physically, and fighters stronger still, but:
* For many, perhaps most fights, melee damage isn't the only option, and a party focused on something else (say, magic damage) won't need to rely on melee.
* The fights where you actually need to rely heavily on melee typically don't have that many enemies, and it turns out that the limited melee capabilities of full casters, perhaps with the help of haste/superman/bless/armormelt should be enough.
* (Worth noting that a Str/Dex Fighter won't need the help of those spells, while if your party consists of classes that *do* need that help, you likely have access to those spells.)

Managed to pickpocket the Constable's Key.

It took a while before I was able to do it. Turns out that it's easier to steal from a Charmed NPC. (In other words, I actually found a use for that spell other than practice!)

I don't like killing friendly NPCs; this is especially true if the NPC is a merchant (Crock, Kunar, and Don Barlone, for example).

Without Charm, I was able to steal a decent number of times with my Bard (0 Pickpocket skill), but not enough to get the key.

Charm made just enough of a difference to actually allow obtaining the key.

From what I hear, before the patch it was possible to steal anything on the NPCs drop list, including items that are rarer than they should be like the book of Holy Water or the practically unobtainable Ring of Power (that I'm thinking of modding to make it so that Bela sells it). Also, apparently it was possible to pickpocket Kunar's key, but at least you can get around that by going out of bounds.

As far as daggers on psionics and mages, it's worth noting that:
* The Canezou Dagger looks pretty good compared to other daggers, and it's a quest item so everybody can use it. (Do you get to keep it after becoming a Templar?)
* I believe the Sprite's Dagger (or whatever it's called) is more common than the Rod of Sprites. Somebody else may be using the Staff of Doom. and one might not like the blind effects of the Flame and Ebon Staves.


(By the way, is there a way to go out of bounds in Lower Marten's Bluff? I'm thinking this could provide an alternative way to get the Mindblast Rod.)

On this particular run, both the Psionic and Mage managed to get 100 to Close Combat skill (the lesser of the two evils, as Close Combat matters half as much as Staff and Wand skill, and maxes first, due to controlling attributes (Senses and Intelligence being maxed).
Staff and Wand skill is dependent on Strength and Dexterity, so takes longer to max.
I don't think that there is a way to get out of Lower Marten's Bluff using that setup, maybe using another setup.

Artifacts isn't that hard to train in Arnika with high communications and an Amulet of Healing. Use the flames by the wreckage, the amulet to heal afterwords, and sell and rebuy it from Lord Braffit when charges run out.

Once you learn Heal All as a spell, it's easy to train Divinity, Divine Magic, and (if you have it) Power Cast. For whatever reason, when you cast it at the auto-recast power level, it will be repeatedly cast at power level 1, allowing you to get a lot of casts in a short amount of time. Did that to make my Dwarf Bishop ready to learn Restoration.

Late game, the Renaissance Lute is great for training Music. You need the lute, a level 18 Bard, and 85 Music skill (75 base will work if you have Puck's Cap). Just have the Bard use the lute on themself, then repeatedly Shift-U to keep using it. This counts as practice even if you start with full Stamina, because you pay the Stamina cost before the restoration and skill increase check occur, and the only thing that can slow this down is if you get too many fizzles and run out of Stamina. (Some form of Stamina regen can mitigate this, reducing the time to regain consciousness, but it likely isn't necessary.) Reaching 100 skill this way doesn't take much time, unless of course you have horrendous lick with that last skill increase.

Got the Mindblast Rod, even though it's at the end of its useful life at the current point in the game.

Some points:
* You need enemies to get the T'Rang Guarders to move out of the way. To accomplish this, I just rested until I got ambushed in the middle of the rest. One possible alternative might be to summon an elemental and attack it in the same round (might require continuous mode).
* Then, the code is, of course, 740. (You can figure this out from slips of paper, though one of them requires killing (or maybe pickpocketing?) Z'Ant to get; even with just 2 clues, trial and error should be enough to figure out the third digit.)
* You have to Run in combat mode, pick up the Mindblast Rod during the run, and then run out. Walk will not work, as you can't move far enough walking to get out of the room, causing the T'Rang to turn hostile.

Also, decided to make the glitch dagger again and take a screenshot.

By this point in the game, Music and Engineering should be maxed. Unless you ran through the game as quickly as possible.
Turning the T'Rang hosile is bad, especially if you managed to make the T'Rang flee to the hallways where you can't advance. At that point, you might as well reload.
This game doesn't favor well with Irionman partyies. Too many bugs, the Umpani obstacle course, and the thing we discussed above.

My Gadgeteer's Engineering is something like 97.

My Bard's Music isn't as high (unless you count the Puck's Cap bonus), but it's still in the 90s.

Saying that skills should be maxed may be saying a bit too much, as the last points, particularly the very last point, take a while to gain. When a skill is at 99, the chance of a skill increase check passing is something like 1% of what it is at 1.

Fortunately, the T'Rang Guarders didn't go all the way out, so there' still another way around them.

One other things: There's plenty of youtube videos showing the alliance quest, and I've found some showing the final T'Rang quest, but I haven't found any for the final Umani Quest (which involves destroying the T'Rang mothership, and likely will make all the T'Rang hostile if you do it).

Ironman is something I'll probably never do in any game where it's an option, as I happen to really dislike that sort of mechanic.

I managed to get the skill training up, with enough beers of course (this can take a long time).
The Psionic and Mage managed to get their Close Combat skills to 100.
The Mage got her Staff and Wand skill to 100.
The Psionic is still stuck at 98 Staff and Wand skill. He is swinging his Quarterstaff like crazy, hoping to max out.
This is the disease of perfectionism.

To be honest, those last two points don't matter.

There's only a few rare situations where having a skill of 100 is noticeably better than having 99 in that skill. The one example I can think of is some magic-related skills, where the chance of failure can be reduced to 0 if the skill is fully maxed. Examples would include an Alchemist using Tsunami; based on what I've read, 125 Alchemy and 100 Water Magic is *barely* enough to prevent Tsunami (7) from fizzling. (Has to be an Alchemist, not a Bishop; also must be at least level 24.) Or, a Bard with Puck's Cap can prevent Nuclear Blast (7) from the Infernal Horn from fizzling, though in that case maxing out the skill with the Renaissance Lute is pretty fast.

Also, I was able to change a setting by editing the 3DSetup.CFG file, changing the first line from "Glide2x" (I think that's what it was) to "DirectX7", which means the auto-map is now properly rendering. (And unlike previous systems I've played this game on, Arnika-Trynton Road's automap pops up instantly.)