The only difference is that you can interact with people outside of the arena's and bg's.
Is that what makes an MMO to some people ? That you can walk around and see other players walking around ?
Thats what is called a persistant world that you can walk around in.
MWO has a persistant world that you cannot walk around in.
Not much difference between the two really. (besides the actual game mechanics and RPG elements of WoW etc)
Edited by Fooooo, 08 August 2012 - 08:55 PM.