I think this is the better question to ask.
Wow kind of is getting dated. The graphics? It's more that we've been staring at the same artwork style for several years than them being dated. The mechanics? Most of them get updated at least every expansion. The foundation of the game? This is the thing that is "dated" ... powerlevel to max then raid everything available at max level and/or grind PvP, all for the purpose of getting gear that is used to replace itself.
But before I derail my own thread... I really don't think it matters. WoW's graphics and mechanics and foundation could all be dated, and it won't matter, because no one else is going to put out a truly POLISHED and STREAMLINED game in the next year. They will have good ideas, but the UI will be painful to use, or the combat will be clunky, or the character development will be lacking, or the endgame will be nonexistent, or there will be major technical issues. And a couple issues along those lines are all it takes for the game to flop in the first few months, and then it will just be like EQ2 and V:SoH and AoC and WAR and all... another failed WoW-killer that will go free-to-play-cashshop-downhillslide within 6 months of release.