I'm probably overthinking this, but after 16 years of this game, one digs deeper. :P
I'm currently running through two different characters (kinda switching back and forth). My plan is to finish BG1 with one of them, then take them through BG2. I'm also planning to stick with -only- the canon party, taking along BG2 NPCs only as necessary to do their quests. So, for BG1, it's Imoen, Jah, Khalid, Minsc, and Dynaheir. Then, for BG2, it's just Jah, Minsc, and Yoshi->Imoen.
The two characters I'm running are a cleric/illusionist and a Cav. The BG1 party is doing a lot better with the Cav. In fact, he's stealing the show. The Cav tanks, while Minsc (with dex gauntlets) and Khalid are on archery support. The girls, otoh, don't really have anything to do. Imoen -can- help with a bow, but it's not even needed. I can put Jah on a sling, but at 1 APR for maybe 1d4+1, it's like a poor man's first level magic missile.
I have the opposite problem with the cleric/illusionist. Jah has the dex gauntlets and is tanking. Minsc is set up to be a dual wielding striker and I send him in after Jah draws the aggro. Khalid is on bow with minimal help from Imoen. If my cleric/illusionist can work a sleep spell, then we're golden. Otherwise, I'm just hanging out with Dynaheir occasionally tossing out a blindness or magic missile. I think I'm eventually going to have way too much spellcasting in this party, as I'll also be dualing Imoen. So, that's effectively 2.5 mages for a level spread where mages are at their weakest.
I'm trying to decide who I want to keep developing. For BG2, I'll have Jah and Minsc, both solid frontliners. Jah's stats are better suited for tanking. Minsc can still be a good striker. I'll have Yoshimo for BS and archery (for whatever the latter is worth). You would think that the C/I would be the easy choice but it isn't. The way I see it, mages are decent strikers, but they make even better controllers. In that regard, I can have that covered when I get Imoen back (which I plan to do pretty much ASAP). Futhermore, with this party, I'll have nobody on 2h swords, and I would especially have to pass up the holy sword. By mid- to late-game, I thinking that a jacked up paladin is going to contribute more than the 1/2 cleric & 1/2 mage. With the paly, Imoen can be on controller duty, while the three of us can hack away.
I should mention that, if I stick with the C/I, I'm going to SK him into a Cleric/Wild Mage at the beginning of BG2. The concept is that Irenicus' experiments twisted his magic powers, which is why he has the wild surges. So, I'll have access to necromancy, but also have the risk of wild surges. This doesn't worry me too much because when I play a WM, NRD tend to be my favorite first level spell.
Anyway, I think if I go with the C/I, BG1 will be a little rough with the mage overkill. I think the C/I will be a real asset in BG2 until I get Imoen back, then we might have some redundancy. However, with the Cav, I'll mow through BG1 with a party as dead weight, and probably still hog the spotlight in BG2. Though, I'll have no arcane support until I get Imoen back.
I know either would work, but what I'm optimizing for is team synergy (not necessarily uber-munchkiness). I don't want charname to hog the glory, but I also don't want him to be redundant. Perhaps neither is a terribly good fit with these party plans and I should consider something else? Anyone care to weigh in?