I think the balance is pretty good with the classes. I've played with just about every combo, and with thought, each has their own strengths and weaknesses, as they should. Agree than Astarion can be extremely deadly when he gets set up in the right spot. I've had a lot of fun playing a dex/wis/charisma based good drow cleric lady. She seems to be able to hold her own as the second fighter, takes the place of Shadowheart for healing chores, and all the folks on the gobbo's side fall for her persuasion easily and love her, much to their regret.