
Role-play pretty much is restricted to Balmung. A few pockets of role-players exist on a few other realms but nowhere near as many as can be found on Balmung.
I used to play on Argent Dawn (EU) back when I role-played in WoW. It was the biggest role-playing realm out of all the RP and RP-PVP servers over on the EU side of the fence. Did other, smaller role-playing realms exist? Yeah, but over time the bulk of role-players all moved over the Argent Dawn because that was where the bulk of the opportunities could be found.
I used to play on Argent Dawn (EU) back when I role-played in WoW. It was the biggest role-playing realm out of all the RP and RP-PVP servers over on the EU side of the fence. Did other, smaller role-playing realms exist? Yeah, but over time the bulk of role-players all moved over the Argent Dawn because that was where the bulk of the opportunities could be found.