I think it's only dex (though not 100% sure), which should be as high as possible anyway for armor class. Don't think extra strength on a mage could be worth it. Might be different on a cleric (or especially fighter/cleric) though, if you want to use them as backup tank in melee.

According to this Strength "may" apply a bonus to throwing weapons (except darts):
[url=https://baldursgate.fandom.com/wiki/Category:Throwing_weapons]https://baldursgate.fandom.com/wiki/Category:Throwing_weapons[/url]

I'm not sure that was implemented though. And even if it was, I don't think investing in strength is worth it for a mage. Better to get dex up to 18 and con to 16, to get maximum armor class bonus and maximum hit points.

I believe it may depend on whether you're playing the classic edition or the enhanced edition, as the EE changed some mechanics.

The problem is that there's only a finite amount of dialog, and the use of pre-made characters limits your options, particularly when interesting classes aren't represented among recruitable characters, or have poor representation (character's stats are ill suited, or suited only for some uses of the class and not others, or the character has a kit that gets rid of interesting (sometimes even defining) characteristics of the base class).

Of course, there's the compromise that I saw in Saviors of Sapphire Wings; all your companions have defined personalities and dialog, but you can change their soul shape (which has the functions that are normally associated with race) and class as you wish. Ironically, this particular game doesn't let you choose the main character's main class; it's always Valiant. (Also, you get situations like Rorone being a healer for plot purposes, but not necessarily a healer from a gameplay standpoint if you, say, choose to make her a Samurai.)

* Mages can't reach level 40, even with the 8 million XP cap that the Throne of Bhaal expansion gets you.
* Level 8 isn't a particularly interesting level to dual class away from Fighter. You get a half attack at level 7, and grandmastery at level 9, but nothing at 8.
* This won't work if your final class is Fighter, Paladin, Ranger, Bard, or any of the 3rd Edition classes, as they can't dual-class with Fighter in the Baldur's Gate games. (Paladin and Ranger can in some of the Gold Box games, and Bards can in tabletop, but not in the BG series.)
* Also, don't forget the ability score requirements for dual-classing. If you don't meet them at character creation, you can't fix that later (one thing I dislike about the system).

Just doing it from memory, 7 is probably the best for the half attack. It’s more the how many levels you can get for dropping one of your main class. And yes, planning is everything, know what you need, know what equipment you are going for straight away (I.e not for newbies).

Haha, yes! I have the only downvoted post in the thread!

Mission accomplished: Heretic Brand acquired. For the Ruinous Powers!

That said. The key points for dual classing in the old DnD ruleset are usually levels 7 or 9. In Icewind Dale (same rules than BG) I had *everyone* reaching lvl 9 in fighter before switching to their "intended" class, to maximize weapon of choice proficiency and get a juicy attack bonus on top of that.

One data point that's worth thinking about when dual classing:
* For the Fighter, the XP required to reach level 9 from level 1 and the amount of XP required to gain one level after level 9 are the same.
* This idea applies to other classes, though the actual level may be different. For example, for Mage it's level 10.
* The Druid XP table is strange. In particular, the Druid reaches level 11 quickly (a multi-class druid reaches it faster than a single-class cleric), but reaching 14 is quite a bit slower, and reaching level 15 requires an extra 1.5 million XP. Seriously, that is one of the strangest XP tables I've seen.

I can see reasons to dual-class at low levels, like 2 or 3. The main advantage is that you can get it out of the way early and don't have to go without your old abilities for long, and you might not notice the loss of level in the target class. (Level 3 gives you weapon mastery, which may be a significant bonus over just specialization.)

By the way, there's one interesting dual-class I saw in a BG2 speedrun; the Mage->Thief dual-class. This lets you choose starting mage spells (spells like Haste and Polymorph Self can be useful from a speedrun perspective), and then lets you get thief abilities to do things like steal to get the money you need (though there are other ways around that). (Worth noting that BG2 speedruns look *nothing* like casual play; the party often splits up to allow for multitasking, unlike in casual play where the party is usually kept together outside of combat, and you see a lot of non-combat use of spells like Haste and (in BG1) Dimension Door.)

I played Icewind Dale 1 and 2 many times before trying the BG series, the reason I didn't want to play BG at first was because I couldn't make my own custom party (well, it was possible using a multiplayer trick, but I didn't know back then). Now I preffer the BG way, but that's because I like the characters in that game, while in games like Pillars of Eternity I rather play with a custom party.

Yes! Imoen is my favorite BG character. :)

Incidentally, I'm thinking that, when I play the Pathfinder games for real, I'm going to use a mix of pre-made companions and mercenaries.

(The Pathfinder CRPGs allow you to create custom mercenaries, but you have to pay for them (cost scales with level^2), and they get a lower point buy than the main character.)

Sorry I don't recall which affect throwing weapons, but yes I assume e.g. dex is important for that. I also always gave e.g. darts and slings to my mage(s), in case they couldn't or shouldn't cast spells.

However, aren't clerics generally pretty bad-ass melee fighters? So if they are not healing the party, they could just as well attack with a hammer or something similar. Or if you want to keep them at the back (for healing the party), I think they can use bows or crossbows quite well?
Depends what you seek in a RPG.

In BG2, yeah the "premade story characters" did add to the story and experience (as I guess they do in Planescape: Torment)... but in e.g. Icewind Dale games I enjoyed carefully building a team of kickass characters of different classes. In IWD games there was not much of story or interaction between your party members anyway.

I still think Advanced DnD rules are needlessly overcomplicated and geenrally not fun. 3rd edition improved on every front, especially in the multiclass department - earlier, imo humans won over everything else simply for "dual class", so much better than having a half-half split.
Even better, Pathfinder got rid of all the arbitrary restrictions like racial favoured classes and actually made "pure" single class builds much more fun to play.

The one thing I *don't* like in 3.x/Pathfinder is that my favorite 2e multiclass, Cleric/Mage, is not viable any more. 3.5 addressed this with the Mystic Theurge prestige class, but that feels more like a patch and still doesn't make that class good enough, whereas in 2e, that class is fun to play and reasonably effective.

The dual-class rules were not as nice as the multi-class split, particularly since, at single digit levels, a multi-class character would only be 1 level behind a single class one. By the time the difference widens, extra levels stop being quite as critical. Furthermore, multi-class characters don't have to worry about the dual-class drawback of missing out on XP when they use their old class's abilities before exceeding their old levels.

In fact, it felt like Humans were the weakest race in 1e/2e, or rather would be if it weren't for racial level limits (one of the most unpopular rules, one that I believe would often be ignored (the Baldur's Gate games don't even implement them), and a very bad way of trying to balance the races). 3e handled it much better; rather than making non-humans essentially unusable in higher level campaigns, they instead gave Humans a little extra boost (one extra feat and one skill point per level).

One more thing: 3e, with its introduction of feats and prestige classes, and its per-level multiclassing rules, made it so that character optimization is a thing. This can lead to power disparities between characters of the same level (because one player is better at optimizing than another), and can lead to builds that break game balance in ways that wouldn't be possible in 2e.

Then again, the famous Pun-Pun build doesn't actually rely on fancy builds to function; a level 17 single class wizard could actually pull it off and rip the game to shreds; all that's needed is the 3.5e Player's Handbook (for the Wizard class and the Shapechange spell), the Monster Manual (for the kobold race), and Serpent Kingdoms (for the sarrukh, the monster with the ability that allows the game to be broken, as it was never intended for the player to get access to it). (There are ways to get this build online at lower levels, but they require other sources.) (I consider this build to be the tabletop equivalent of Arbitrary Code Execution in a single-player computer game.)

I've forgotten the rest.

Yeah, I was going to mention Icewind Dale I and II as well, because as much as I wanted to, I was never able to get into them. Thanks for the clarification though. I understand many people enjoy those experiences, but as for they 'why', I guess that unlike you or others, I never felt that the combat of Infinity Engine games was engaging enough to drive a whole (20+h?) experience by itself. That's why in this case I'd argue that we're not talking about RPGs but aRPGs or something more action related like hack and slash.

There're many RPGs which allow the player to customize their party, go solo, or recruit mercenaries and spec them to their liking. In those cases I wouldn't say written characters limit the game's options; in fact, I'd even argue that limiting the player's options to a party of defined characters shouldn't necessarily be a bad thing.