WOW Killer - a term that originated somewhere in time and is a referrence to something that will result in World of Warcraft's millions of players to permanently stop subscribing to the game. Short of an asteroid I do not see this happening anytime soon lol.
To date no MMORPG has been able to do this and there really isn't a title in the horizon that has the potential to, oh wait did someone shout SWTOR! hoorah! ? ehrr please sit down, no it will not from what's been leaked out not by a long shot LOL that's right I'm laughing out loud.
So Why no WOW Killers? Why not EVE, Vanguard, EQ2, FFXIV, WO, LOTR, etc etc etc etc?? why can't they bring WOW down?!
Well in my greying haired opinion, after observing and participating in the world of MMORPGs for the last 15 years, World of Warcraft is the only one I've played that has continuously focused on subscriber retention with everything revolving around this purpose. The rest of the titles I mentioned and MMO titles yet to be released are caught up in the other aspects of design and they have and will continually come up short of the G spot.
What makes a WOW Killer then? Maybe those thoughts floating around in your brain makes em, or maybe what's in my brain does. But it is a very valuable commodity, worth its weight in gold.
I am done with my rambling, it's raid time for my level 85 Goblin Rogue ;)