It's intriguing that some people believe A high fantasy MMO has to be a WoW clone. To these beautifully, intensely stupid people, I respond with Everquest. Around long, long long before WoW, easily as addictive in its day, and, oh! Lookit that! High Fantasy!
No MMoRPG will ever be a "WoW-killer" barring really damn weird circumstances. No MMORPG can stand up to WoW, not at release anyway, for all the reasons people have already given, ESPECIALLY the one regarding time devoted. I just lost all my PS3 data (flipped a switch a half-second too early. At least it was my own fault and not the system killing itself like if I'd bought a 360), and it is crushing. On the one hand, I like Devil May Cry 4 and Resistance: Fall of Man enough to replay them, and getting all the stuff I had back won't be too hard.
But Final Fantasy XII? That was 80+ hours of play. And a lot of that time was leveling and sidequests. I have a PS2 and a spare memory card with plenty of space, but right now even thinking about picking the thing up again kicks in a strong aversion for me. And this is a SINGLE-player RPG.
I can't imagine one where I have friends involved as well, a ton of stuff, significantly more time and a good deal of my social life, which is to my understanding what WoW is for its players. And since everyone in the entire world who likes MMO's is playing the game, this leaves only a small percentage of people who could be interested in the concept to get involved in any new MMO that comes out.
A high fantasy MMORPG is not by needs a WoW clone, and you are a very special kind of stupid if you think it has to be. Emphasis on special. And stupid. Hell, I can just put "WoW fanboy", with the notation that you're embarrassing even that group. But a high fantasy MMO cannot help being compared to WoW, and no matter what that's going to hurt it.
And again. Almost every MMORPG fan is already playing WoW. It doesn't really leave you with a big pool to draw from.