I like the Rock...but dear god he counted act to save his life, its just a slightly different written variation of "him" each and every single damn time. At Least Arnold went and tried different types of films, did the harder R films etc. Rock is just about that cheap CG Disney muck. SO many of his films I forget even existed, that one with the Tower, and one with a Monkey, did anyone even remember he was in them? Think he did a disaster film film, all of them straight into the trash bin never to be watched again.
He does play very similar characters. The trouble is, with how he looks and how he is known, it is going to be very difficult for him to play completely different characters. I can't see him doing a Christian Bale or similar and going mega skinny or mega fat for a role!
Fortunately, he is a very charismatic person with a very good screen presence so he is good in the roles he plays.