People freaked out when they heard that Johnny Dangerously and Mr. Mom was going to play Batman. And again when the co-star of Swing Kids and Reign of Fire; they didn't think he'd really have the range or gravitas for the part. And again when they heard the star of A Knight's Tale and . . . well Brokeback Mountain would play the Joker. They didn't think he could be funny enough. They were all shocked when it turned out that actors could act in different roles.
So I say give Mr. Reynolds a chance. I'm more worried about the quality of the script or director. Too many "Hollywood Blockbusters" with high profile names and turd writing and/or directing to have any other reaction.