The classes in Neverwinter Nights are not NEARLY balanced enough for a MMO. If you know what you are doing you can create a "god" class that is literally unstoppable. They would have to alter the D&D rules pretty severely to make this work.
Level this character up in NWN2 and see what I mean
You can kill most things in 1 hit and most bosses in like 3 hits. It's sick.