What other franchises would you be interested in seeing in a game like this? Star Wars is probably my favorite franchise of all time, but I think there are some other things I'd totally invest in if they were available.
Personally, I think Lord of the Rings would be a strong contender- FFG already makes LOTR licensed games, anyway. The only issue, of course, is that it's thematically pretty similar to Descent. Game of Thrones kind of fits the bill here too, though perhaps thematically not quite as well as LOTR.
One sort of "Left Field" idea would be something based on Steven King's The Dark Tower series. It could be set before the fall of Gilead, and have generic gunslinger heroes. What's cool is aside from the Dark Tower themed enemies that would surely be included, there could also be other King related enemies in the campaign, like Pennywise or Kurt Barlow.
As much as I'd love a King set, I think one that would probably sell much better is something based on Marvel or DC. I think the best way to handle something like this is to simply let the heroes be actual Marvel heroes rather than generics, since canon is much more of a complex issue in comics than with something like Star Wars. It'd actually be a blast making a team of 4 very distinct heroes and battle minions and supervillains.
Also, I'm a huge Assassins Creed fan (so much so that Ubisoft is actually sending me to E3 next month), so I think an Assassins Creed thing could be cool, but many mechanics would probably have to change to allow for more of a stealth component. Maybe the Clawdite can be of some inspiration once we see it.
Anyway, any other thoughts on franchises that would work in something like IA?