That sucks that Fantastic Four and X-Men are off-limits regarding media exposure just because Fox owns the movie rights to the series

. I guess.....they could work out a deal with Fox and gain creative control over those IP's after the release of the new films sorta like what happened to Spider-Man after Amazing Spider-Man 2 came out (where Disney, Marvel and Sony Pictures worked out a deal that makes all of them happy).
I could see that happening, as I'm sure Marvel would love to use Wolverine in a future Avenger film or use X-Men/Fantastic Four for a future Marvel Playset for Disney Infinity

.
I guess this brings up the complicated questioning of IP control and how it affects the larger picture

. Regardless, the most fan-favorite characters (Wolverine and Deadpool for example) will appear in a MvC4 if one ever gets made, as Disney and Marvel know how popular they are (and with Wolverine, he might as well be the Ryu for the MvC series XD).