I feel like I'm fine with 4 because Larian's quality of life for many things making 6 just not fun to even imagine.
It's sad to say but many people asking for 6 aren't thinking about having to manage that in Larian's schema. It's just too cumbersome.
Maybe if you had 6 individual players.
The sad thing is that most tried 6 and still want it to be implemented into the game.
The actual problem for me of having 6 is a question of difficulty/rebalance, still not answered sufficiently in hundreds of posts. The most common answer seems to be, "let difficulty as it is" and use the usual settings (like Story Mode, Easy, Classic, Hard, Masochist, Real Man, and so) to overcome the consequences of having 6.