If you really want to destroy try Human Level 9 Kensai, then at level 9 dual-class into mage (what Tallima mentioned).
Try for stats at least like Str15, Dex18, Con16, Wis9, Int17 and Cha7.
Since the XP cap in BG 2 is 2,950,000, a Kensai that reaches level 9 will have 135000 XP, leaving 2,815,000 experience points for the Mage class. A mage needs 2,700,000 XP to get to level 17 (when you get level 8 spells), so you can effectively max out your mage class as if you were purely a mage, while reaping the benefits of a Kensai. Nice, eh?
The Kensai/Mage dual class synergy is so effective you can actually solo through the game with the one character if you're hardcore enough to try. Give it a shot, see what you think.
BGII is a cheap cheating game x.x I died so many times its not funny
It certainly doesn't hold your hand. The quick save button and the difficulty slider aren't so much game features as they are core game mechanics which you must master