I think the biggest thing going against Marvel vs Capcom is that the last one didn't actually do that great (~2 million copies), and it's not entirely clear to me what is supposed to make this one do notably better given how Street Fighter went.
I could just straight up be ignorant of some major changes or hot new features, but if it's basically the same thing as before, I don't see why that is notably more appealing half a decade later. It's not like Marvel was irrelevant in 2011, and even if that half of the appeal has went up, Capcom's has presumably went notably down.
I doubt they would let Capcon deliver junk, but at the same time I doubt a lot of just Marvel fans will pick up. It has Marvel characters, but in a highly technical fighting game. But they still got Spiderman(is that 2017?)