As a new face around these parts, I just wanted to go ahead and add my +1 for the option to have a larger party size. With release right around the corner I know it's a pipe dream, but still.
I just don't like 4 party members in CRPGs. I've always played tabletop with 5 or 6 with my friend groups so it's what I'm comfortable with. I did play Solasta and I managed with 4, but I didn't enjoy it. I DID enjoy using the mod for larger parties, even though you could only do it for the player-made campaigns. (But I came across one issue with moving between screens which is why mods will never be as good as native inclusion in the base game.)
I'm also not a fan of mods since they can face issues with patches. I'd hate to be in, say, Act 3, only for a patch to come around and either keep me from playing my file or, worse, have it corrupt/fail altogether and force me to start over. Plus I don't trust myself with when it comes to fooling around with files. I'm terrified I'll mess something up.
The devs have said and shown multiple times that they are all for players approaching the game with a myriad of strategies. Well, my troglodyte brain's approach is to throw more bodies at my problem.