My point was that you already feel the sting of a small party with the origin characters. You'll feel it a WHOLE lot more with custom mercenaries added to the game.
Like I've said about multiplayer, so it will be with custom characters mercenaries. The more non-origin you have, the more punished you are because you can't even trigger many origin story events - or you need to switch out companions constantly to do so.
Party of 4 customs means 0 opportunity for origin story quests like Lae'zel and the Gith creche, Wyll and Spike or Shadowheart and the Selunites/Sharran war. If you had party of 6, you at least have 2 party member slots to put origin characters in. Now, you can still have story quests.
At least with mercenaries I would hope you could Leave At Camp. You can't do that with 4 player multiplayer. You play 4 players and you completely lock out all opportunities for origin story quests.
And again, Party of 6 allows them to take present encounters and balance them more appropriately with 5e rules. They wouldn't need to nerf monsters as much. 3 intellect devourers are much more fight able with party of 4 customs and Shadowheart even at level 1 than they are with just Shadowheart and the MC. Also, 3 REAL 5e imps are much more doable with party of 4 + Lae'zel than just Lae'zel and MC.
And finally, I've asked you before, Ragnarok, to be respectful. Your comments are not. Please refrain from "duh" - like nonsense that does not provide any constructive use at all. It's insulting and unnecessary. I do not appreciate it. Thank you.