I mean...it's hard to say because if you want to actually be able to play through the game...you're gonna need to kill stuff. So a useless character would be like a ranger that is all ranged but only uses a dagger...basically useless in combat. or a fighter that is STR out of his mind with all melee abilities/features but then only uses throwing stars or something useless like that...but could you actually get far enough in the game so terribly optimized? who knows. so it really depends on how terrible you want your characters while still being able to actcually play the game. and since it's point buy, at least in EA, don't give the character the stats their class needs? a fighter with 8 str and 10 con isn't going to be effective and probably won't make it far in the game...