I can see how making a superhero scenario would be difficult. You could start with a basic scenario like the secret wars mentioned above, or you could go with the onslaught saga, the marvel vs. dc storyline, or you could even make a unique scenario such as apocalypse attacks or something like that. You could have some generic buildable mutants for the basic units. Since you shouldn't be able to build the notable heroes and villians, you could just preplace them at their first appearances and then just upgrade them to their later versions, or since comics have a habit of reviving fallen heroes and villians, you could just make them so expensive that you'll only want to have one of them at a time. You could have the tech tree coincide with certain events or things in that comic's particular universe. For example, spiderman starts out as just the basic spiderman, with the discovery of the symbiote he would upgrade to the black costume, with the discovery of the sonic ray gun, he would upgrade back to a stronger version of spider man, and then venom would come into the picture. I don't think that this would work out too well with the AI, but I do think that it could make for a really fun mulitplayer game. Just a thought, what do you guys think?