You know what would be epic? If they threw in Ultraman, and then for Super Hero Taisen 3, they keep the villain's identity a secret. Like, no leaks, no putting in a magazine. Nothing. Not even a damn teaser in the opening! They'll keep the big villain a secret, or if they have to, throw them off by saying "Oh, Belial is back and fucking **** up. Again." And then, after the big climatic team up, one of the Riders points to the ocean and says, "LOOK! THE ENEMY LEADER ARISES!"
And then it comes. Rising out of the water like an old Lovecraftain horror, all set to the sound of a familiar violin rhythm. The audience who recognizes the song are shitting their pants, going "****! IT CAN'T BE! CAN IT!?" The other audience members are looking around going "wtf is everyone doing reacting like if Nanoha is about to blast through some walls?" and then the mighty radioactive lizard rises out of the water and unleashes a mighty signature roar complete with its theme song in full bloom, and in response, the audience gives out a roar of their own. Pants are to be darkened.
Seriously, that **** must happen!