i agree that Keldorns True sight and dispel magic are EXTREMELY helpful. Yet he disappointed me when I saw him first. I was glad to have a Paladin as another Healer in my party (I started my first run through SoA on Core Rule diff and just hated to sleep). and then he is nothing but a tank that can't specialize in weapons for more than 2 slots. The really sad thing is, that there are not enough evil characters around to make a completely evil 6-member-party in solo game.
As for Mages: Nalia becomes surprisingly powerful in the course of the game and Edwin is just "masterful".
It's also sad that the only bard in the game is a Blade, so he gets a downgrade on the Bard's specialty Lore (not that you'd need it anyway).
However, maybe the NPCs have their strong sides and their weaknesses -as every RPG char should have - because the guys at Bioware didn't want to sit endless nights to roll a 94
or because they are no Bhaalspawn like you (what about Imoen then)