I hate mods, and I don't need party of 6, but I'd like the option especially since it's already there. They just need to let us do it. They've locked it behind a max party size number of 4. Nothing more.
It's not about whatever you just said. It's that I'd like a little more party freedom. I'd like to travel with ALL the current origin so I feel more like a full party. I like the character interactions more with the party of 6. Id also like the freedom to make 4 custom characters and yet still take origins with me for side quests. I'd like to have a wizard, a rogue, a cleric, a fighter, a warlock, and a druid all in one party if I want. I don't like having to trade characters in and out because of side quests and all because they feel more than 4 is too full up.
Basically, there are a ton of reasons why I want party of 6 as an option.
