3 minutes ago, Iuchi Toshimo said:Hulk, Black Widow, Spider Woman, et al. are all already just allies so I'm guessing not everyone gets to be an identity. I mean, there were 60+ characters in the movies and with a release cycle of 1 every other month that would be about 9 or 10 years to release all of them as playable characters.
The LotR LCG has several examples of a character showing up as an Ally card as well as a Hero, so that's not really a concern, actually. Plus the rules say Uniqueness only matters by Subtitle/Alter-Ego--which allows, for example, another "Spider-Man" to come alongside "Peter Parker" so long as his name is "Miles Morales" or something else. (It would be interesting to see a Superior Spider-Man at some point, though since he's still in Peter's body I... don't know how that would be best resolved.)
As for release schedule, you're also not accounting for larger box releases. Not sure how often we'll get them, but it seems likely we'll get some sort of X-Men "mini core set," since everything so far has been Avengers focused. Guardians of the Galaxy, Fantastic Four, and plenty of other groups could see similar box sets at some point, which would escalate the release for new heroes even more.
That doesn't mean everyone will be a Hero, no. In fact, it seems likely to me that the Ally card for each character (Shuri for Black Panther, Rhodey for Iron Man, etc) will never be Heroes, as it would mean being forced to include an effectively dead card in your deck to play those heroes together. Which is okay, since those characters are relatively Side-Kick-y... But it'll be interesting to see who all gets put in that role. (One alternative, I suppose, would be that a Rhodey Hero has Stark as an Ally, and you just don't play those Heroes together... But I doubt that.)