Why: Singer has had plenty of experience handling films with superheroes, albeit with actual powers. His most recent directorial efforts haven't incited as much excitement as his X-movies, so perhaps its time for a return to the genre he shined in.
Key Scene: A top FBI agent interviews people who were present during a botched bank heist thwarted by Kick-Ass. One of them is Dave Lizewski who's asked 'Who is Kick-Ass?' by an FBI agent.
Likelihood: He's pretty tied up with Jack The Giant Killer at the moment, and he could be called in for producing duties on the much-mooted X-Men: First Class sequel.