Oh yeah, the EQ-WoW style of MMORPG probably wouldn't work very well. I just don't see a Sheriff "class" being very good. A large sandbox style map with leveling skills through use like in Skyrim instead of picking a class might work best for it.
---------- Post added 2012-04-06 at 02:59 PM ----------
I'm thinking about the old movies too but I'm probably emphasizing different parts of them for "Westerness."