IMHO, that would be good for tactical slasher, but totally wrong for game with some role playing inside. Premade companions won't have their own story or quests, won't speak to you or to each other, won't do any of that stuff people loved in BG2 or P:T. Generally they won't seem to be alive. It just like you start with six guys (gals, whatever) instead of one, convenient, but not interesting. Which one of them would be YOUR character if you create them all by yourself?
I think it's all just about different playing styles, but it's rather difficult to put them both in one game. Adventurer's Hall could do the trick, but it must have its restrictions. That would be somewhat unfair to game balance if you could walk through the dungeons you supposed to beat alone with five more folks at your side, crushing everything to dust with that big nasty boots of yours... Oops. Sorry, lost my point.
Anyway, some people would prefer it your way, some other wouldn't, and PoE supposed to mix it up.