The similarities between the 'gee-whiz' personality and reluctant heroism of Night Owl (a.k.a. Dan Dreiberg) in Zack Snyder's Watchmen and the wholesome nature of Barry Allen are clear to any comic fan. So in some ways, audiences have already seen Wilson tackle the subtler aspects of Allen's character - as one of a troubled film's bright spots.
He may not have the blonde locks, but Wilson has the right mix of likeability, good looks, and quiet humility that a big screen incarnation of Allen needs. Since he's made a habit in his career of stealing scenes from established actors, Wilson has proven he can carry his own alongside the likes of Ryan Reynolds and Henry Cavill.
It's too early to tell if DC and Warner Bros. will wish to take The Flash's JL role and possible solo movie as seriously as Batman and Superman, but we'd bet Wilson could handle it, either way.