Alter Ego - should it be a cooperative game?

A few people have suggested, presumably based on the theme, that Alter Ego might ought to be a cooperative game. A team of superheroes defending the city from arch villains does sound like it would lend itself to the coop genre. I hesitated at first because as yet I have not seen a good way to make a cooperative game, at least one that wasn't Solitaire by Committee. Coop games ARE somewhat popular though, even if they are SbC, and the theme DOES suggest cooperation... Maybe deck building will force each player to be in charge of their own contribution at least a little, as their deck is their own and would differentiate them from other players.

So if I were to revisit Alter Ego as a coop game, what would have to change? Maybe not that much. How does this sound?

First off, there could be a supply of Civilian (CIV) tokens. Villains would take CIV tokens out of the supply, and when that supply runs out, the villains have taken over the city, the game is over, and the players lose. Each turn a player turns up a Villain card, and place a CIV token from the supply onto it. That villain could be said to have taken that CIV token hostage. Upon defeating that villain, the CIV token could go back into the supply.

After the new villain arrives, the player gets to resolve the cards they have in play (from last turn, see previous blog post). It could be the case that villains show fewer symbols, corresponding to the 'cost' to knock a CIV token off of them, and they could take multiple CIV tokens at a time - removing the last CIV token would be how you defeat the villain. Defeating the villain would still give benefits to the player who did it.

Arch Villains
It might still work to say a player must collect enough of an Arch Villain's icons (on villains they'd defeated) in order to go after that Arch Villain. But perhaps rather than 'qualifying' to attack an Arch Villain, there could be a tracking board as well, and when 'enough' henchmen of the proper type are defeated, the Arch Villain of that type arrives. The Arch Villains would be big, bad versions of the regular ones, and would take a larger number of hostages, or maybe permanently remove CIV tokens from the game, or something similarly dastardly and difficult to deal with.

Winning the game could be defeating all (3?) of the Arch Villains before they and their Henchmen overrun the city (by removing all of the CIV tokens from the supply).

Flavor
For additional flavor, the CIV tokens could be tiles or cards which have various TYPES, and it could matter if too many CIV of a particular type are hostage - making different reasons to go after particular henchmen at different points in the game. Like you've got the cards to defeat this guy, or you like the abilities you'd gain, but THAT guy has the MAYOR hostage, so you need to save him first.

This is still very rough draft-y, so please feel free to chime in with comments! Does this version sound better than a competitive version of the game?