We aren't some Joe Schom, we are the Champions of the World. We stopped Nefarian in Black Rock Mountain (and again in Depths), we stopped C'thun and Yogg Saron, we toppled the Lich King's reign, we stopped Death Wing, we stopped Garrosh and his Iron Horde and we foiled Guldan once. We are the heroes that the characters of lore need. We are legitimately the strongest characters in the world and the only ones trustworthy enough to get the job done (lore wise).
The MMO part is dilutes the RPG part, but we still are "The Man/Woman" of the Universe.