Exactly.
The problem with having hero v. hero in the climax is that neither side wins. I don't believe Marvel is going to risk a climax where things come to a draw. Instead, they unite against a threat they can beat only together, but without resolving their differences. Friendships are still destroyed, Cap is still dead/retired, Tony is also likely retired, and the S.R.A. is hopefully still in place. This way, the good guys can still "win" against the bad guy, but without it coming off as a cliche "put aside our differences and hold hands in a circle singing Kumbaya".