Sorry EAWare but a single planet is not considered an expansion for any mmo.
Yeah! it isn't!
I mean.. Outlands wasn't a single planet! (it was actually merely the remnants of one)
Northrend wasn't just a single planet! (it was only a single continent)
Pandaria wasn't just a single planet! (again, merely a single continent)
Rohan isn't a single planet! (also, merely a single country)
Until anyone knows how big this actual 'single planet' is, you have no right to make this bold claim. So just hold your cards a bit closer to your chest and wait until we actually know things instead of shouting stuff like that.