Originally Posted by Ikke
That is difficult to prove. I can imagine there is quite a bit of balancing involved in the capabilities of individual characters. With a party of four, each individual party member will probably need to have extra quality to compensate for the lack of quantity. Also, it is imaginable that set pieces of the story depend on the number of characters (e.g. being thrown in jail and having to break out one by one).
You are just making up additional developer work here, which is exactly what I said in point 2: exaggerating things to create a strawman that can then be opposed.

Originally Posted by The Composer
So far the best suggestion I've seen is just what Fuji said, increase party size cap with warning of not being intended experience. Game will be significantly easier, inevitably so. But all that requires is a change in a handful of story goals (individual pieces of scripting that controls how parts of the game works), and... To really generalize and not write a wall of text, add two more triggers (indicators for the game to know where to place player characters in certain situations, such as dialogue, camp site for where they stand, sleep etc) and the new dialogue cinematic systems that presumably also has triggers to dictate where player 1-4 stands (hence if you mod now, sometimes two characters stand inside each other, because they both end up sharing the same trigger).
What @mrfuji3 said and this is exactly what the vast majority of those of us seeking the option have said from Day 1. But the people who want the game to cater only to them and no one else, knowing that this option description above undermines their entire opposition, ignore what we say here and instead create the strawman of our request creating all kinds of huge changes to the game that they keep pushing again and again. It's a deliberate strategy to deny something to other people even though what those other people want does not affect them in any way.