Why do I think it's too difficult to balance? Because this game isn't my first rodeo and balance in games that are 15 years old is still not possible. You'll never have perfect balance, especially if you get new content added.
I'm done with this discussion. Larian changed it to four for a reason, I don't get why it MUST be changed. I'd rather them leave it alone and get the game finished faster.
And the graphics problems fixed. Grr.
Not sure why you're done with this discussion, because this ^ combined with your earlier post about "feeling compelled" actually echoes/complements my thoughts.
It's not that it's impossible (you've used "impossible" and "difficult" interchangeably) for a 6-person party to be good, it's that you think it will take too much development time away from other parts of the game. OR if Larian implements a simple fix - adding the option for a 6-person party without adjusting balance - you'll feel compelled to play with 6, making the game too easy.
I feel similar; if the game is not locked to 4 players by default, I'll feel compelled to play with 6. And, particularly because of the toilet chain/UI but also just in general, I think I'd have less fun playing with 6 characters. And thus the argument for a hard toggle hidden in the game settings as a compromise between my and others' desires.