Hickory: Erm, no actually. The OP clearly stated:
"I was originally planning to dual Imoen and myself into a mage, but at level 9, where the game would be pretty much finished and I would be on my way to BG2."
and also:
"I'm running BGT"
So BG2 and onwards was very much in mind.
Fine. That doesn't change the fact that your kensai PC will be subpar for all of BG 1 and most of BG 2 when AC matters.
Hickory: Are you joking? A plus 1 To Hit every 3 levels is *massive*, especially when you factor in Kai. And Strength is not even a factor -- a Kensai can have equal or higher Strength as any tank character. I get the impression that you've never played as a Kensai.
Exaggeration much? +1 to hit every 3 levels is far from massive for a fighter, considering all the to hit bonuses you get from strength, proficiencies and weapons. Furthermore, as you said yourself AC stops mattering after a while, and so does to hit for warriors.
As for Kai, given that damage range on a weapon is a small part of the damage you'll actually do, it's a fairly useless ability. When you're doing 20+ guaranteed damage per hit from strength, proficiencies and your weapon enchantment, whether your roll a 1 or an 8 on the damage roll of your longsword isn't that important.
I've never played a kensai PC because I dislike the concept, but I've played all of BG 2 and ToB with a pure kensai NPC in my party (IIRC, Chloe from the mod of the same name) and she didn't do much more damage when fighting than, say, Minsc.
OTOH, you had to constantly micromanage her to pull her out of melee each time she got aggro, so overall she did less damage than a straight up fighter.
gaming-freak12: 1) A fighter/mage is not meant to be a pure mage to begin with; the whole point is to use the protective spells to make them harder to kill in melee range. That's how a fighter mage, and in fact, a Kensai/Mage is supposed to be played.
Yes I know how to play a fighter/mage thanks. What's your point? The fact remains that your fighter/mage is a better tank if he can actually equip armor and shields instead of constantly having to rely on buff spells.
gaming-freak12: 2) I'm guessing you haven't rolled a kensai through BG1. I did it just recently, with a non-power gamey party, and I pretty much decimated half the enemies I crossed by dual-wielding longswords and utilizing Kai with Draw Upon Holy Might, which is one of the unique powers you can gain outside of class restrictions. And are you kidding? the game CHOKES YOU TO DEATH with defense potions. Not that it matters since you save those for tougher mobs and boss fights anyways.
That's not much of a claim. BG 1 can be soloed, so with a full party you'll be slaughtering most of the enemies you come across, no matter what kind of PC you have, provided you have a clue how to play the game.
As for drowning under defence potions, that's just not true, unless you buy them. I'm playing through BG 1 with a bard right now, I'm starting the cloakwood areas, and I have 6 potions of defence in my inventory. And no, I haven't used any.
Anyway, It's obvious we're not going to agree on kensai, so I'll stop here.
I still think the small damage bonus you get is not worth the gear access you lose, and is much worse than the immunities provided by berserker rage.
Feel free to think otherwise.