I mean, do you think the name "Captain Marvel" is the reason why he never regained the top spot in comics? I'm not saying brands don't matter, but switching from "X-men" to "X-Factor" or "X-Nation" would be an easy transition from my point of view. A new name for a new era. Don't even make it about "correcting a name" but about a new symbol for a new direction.
Though I'm not a fan of the titles "Dawn of X" and "The Mutants".