Willits really isn't a centerfielder so he'd be a compromise there. He's basically a role player with exceptional on base skills who can also play very good left field defense.
His impact wouldn't be tremendously different IMHO than Reed Johnson (though each have unique skill sets) who the Reds could've had for free.
Willits probably wouldn't take ton to acquire but the Angels probably wouldn't give him away either. Dunn for Willits would be a head scratcher.