Gotta love the whole "You would hate a turn based system with six men" some people are attempting, by the way. No, I fucking wouldn't?
I said that I'm playing Pathfinder with the turn-based mod and loving [almost] every minute of it... And that's not even a game with encounters DESIGNED for the turn-based mode.
This right here says it all. And too from a TB fan and not someone like me who's a RTwP fan.
I would add the argument that parties of four can be ok in games that have a classless system, like the D:OS games and also the Dragon Age games. But in a system that not only has classes but where classes are a core feature of the game and include additional levels of detail such as subclasses and multiclassing, a party of four is extremely limiting. Most people will just end up using the same small subset of basic classes to make up their party of four, and never get to use any of the other more esoteric classes available in the game because there's no available spot in the party for them. This same issue also goes for companions. The more quirky and unusual companions will get no playtime because including them may make your party effectively a three-person party.