If they are planning a Lone Wolf mode then why are we even debating this? You're confusing. Let them create a Lone Wolf mode for you, and a 6 party game for everyone else. Why are you fighting for a 4 party game instead of 6?
I think she's made pretty bloody obvious that this isn't about making a sensible argument for a design decision but about defending the status quo no matter what. And no mirror will be left unclimbed in the attempt to achieve that goal.