Lol. I'm not happy about 4, but think about it. How many RPGs truly have a 6 member party? The Final Fantasy games? Neverwinter games? Solasta? Knights of the Old Republic? I mean, other than BG1 and 2 and Icewindale, what other 6 party RPGs are there?
So yeah, Id like 6, but Im okay with 4 if there is a decent reason for it and especially of they explain it well in the story.
Baldur's gate? Baldur's gate 2? Planescape Torment? Icewind Dale? Icewind Dale 2? Several Might & Magic or Wizardy Games? Temple of Elemental Evil (up to 8 with enough charisma, actually)? Fallout 2 with 10 Charisma? Pillars of Eternity (and the sequel got a lot of backlash for capping at 5)? Pathfinder Kingmkaer? Pathfinder Wrath of the Righteous? Solasta makes you create 4 characters but it gives you OFTEN chances to fill the other two slots with temporary NPCs?
I could go on but I think you got the point.
Just because other, lesser game on the downward path of absolute DECLINE decided that as a console player you were too stupid to manage six it doesn't mean its should be embraced as a standard in a PC game.