Also, when slagging off NRS for Injustice can we at least do it based on the most recent patch which is actually really damned good?
Many years ago I couldn't imagine Marvel vs. DC happening. The thing is, there is SO MUCH MONEY to be made from this now both brands have fully broken out of the comics and into mainstream media (yes the odd character has done so before, but not like now with the Marvel Cinematic Universe, X-Men film revival, new Superman, Nolan's Batman films, etc) that pride kinda gets pushed to the side. Both sides would hugely benefit from it both in terms of exposure and money.
A less world-shattering option is that NRS could just make a pure Marvel fighting game. I don't think there's been a good pure-Marvel game for years upon years: DC gets the Arkham series, Marvel gets Deadpool lol