User blog comment:Jacknapier10/Which characters cannot appear in the Marvel Cinematic Universe?/@comment-3317214-20140427001138

Well, it looks like you already know who can and cannot currently appear in the MCU. So I'll say this, theoretically, any of these characters from other studios could appear in the MCU if one of three things happens: But yeah, other than that, there are some characters that Marvel does have that I doubt will appear in the MCU soon, such as Punisher, Ghost Rider, and Blade. But I'm okay with that, as I don't really like them.
 * Some kind of deal is struck between the studios to share a universe (never gonna happen)
 * Disney will offer a lot of money to other studios for certain character rights (not gonna happen any time soon - they've got a lot to work with already)
 * Or, the contract for the other studio's rights will end and the rights will revert (maybe this will happen for Namor and Man-Thing - are they even trying to make movies for them?) I think the go with Fantastic Four, is that they have to start filming in June.