2010 is too early.
A 2 year development cycle is really pushing the boundaries for the level of quality you can have, even when sequels are starting with all the underpinnings (game engine, pre-existing cast of characters, in game resources) in place.
But I'd likely pick up a sequel to infamous if it were released in 2011, assuming they improved and added to the formula (likely, Uncharted 2) rather than change what worked in the original (Resistance 2).
If Sucker Punch wanted to, they could easily do a sequel with a new cast of characters, a hero/villain with different powers and a new city, despite the somewhat open ended conclusion to the original which I found satisfying, even though it ends with you running around an enemy free city, closing up any little details you might have missed. I wasn't terribly attached to any of the characters in the game; not sure if I'm in the minority here.











