I believe that a board game utilising the core mechanics of Descent-2nd edition and based in the Marvel Comics Universe would be:
1) do-able (design-wise)
2) extremely fun to play
3) it would sell BIG.
The way I see it it should let the "good" players impersonate classic Marvel heroes (no hero-creating mechanics) and the "bad" player impersonate one of Marvel's evil masterminds (Kingpin, Doctor Doom, Red Skull…)
The "powers" could easily be managed by cards (in a similar way to Descent-2nd ed.) and the heroes, just like evil masterminds and their hunchmen, would be presented by miniatures.
Some importance should be given to the "narrative" aspect of the game (short game-sessions punctuated by objectives, investigations and cliffhangers)
I would figure some (not too many) miniatures to represent side characters which could play the part of objectives or help develop the "narrative" (es: kidnapped Aunt May; Nick Fury to be met in an alley in order to receive directives..etc)
Here is how i imagine the commercial format:
A core set containing: a small campaign set in New York city, broken down in a few interconnected scenarios (but playable indipendently); the tiles to represent N.Y.streets and possibly some interiors; a few classic (and movie-featured) Marvel heroes (es:Spiderman, Wolverine, Ironman, the Hulk, Captain America, the Black Widow); one evil mastermind (es:Kingpin) some low level hunchmen/minions and one/two high level bad guys (es: Bullseye, Electro)
After that millions of otions could come out as expansions/theme sets complete with new heroes/bad guys/campaign/tiles: Avengers set; Fantastic Four set; X-men set…..and BILLIONS more…..
Let's be honest… who wouldn't buy such a game?
The only problem I would see is with acquiring such license from Marvel…. do you guys at FFG believe it would be possible or not?