Wow is quite old yes, every new expansion brings something new and exciting, always something big! Something Mir will never do even the Korean and Chinese servers.WoW is dated as fcuk as well lol. I tried playing last week but couldn't bare how bad the graphics are. Looking into playing Wildstar when its released though.
Difference between WoW and Mir is I always have something to do on WoW and never seem to get bored, I never find myself standing in town like I would mir haha!