I've found that incredulous since the casting.
A character known for his height and size and face that shows the scars of fights . . . which comes into play frequently in every plot . . . and Cruise gets the role.
By the way, the character Reacher grew up the son of a Marine, but he was a U.S. Army Military Policeman (reaching the rank of Major) through and through.
I had the same feeling when Cruise was cast as LeStat in Interview With A Vampire. Rutger Hauer or Julian Sands would have been perfect for the part.