I've never personally liked MMO's except two. I've tried every mmo, and they just can't keep me. Guild Wars 2 was the last straw, it wasn't what I expected, and a big let down after all the hype.
I liked Runescape when I was a kid, and World of Warcraft when I was older(teens to early 20's). The fact that I spent so much time in WoW when I don't like MMO's at all says something about the game. I really miss WoW still though, very nostalgic memories.
What I hope is project "Titan" is another good MMO from blizzard, like what WoW used to be, that carries some of the elements over such as: art style, almost fully open world, big cities, etc.
Blizzard has really ruined WoW too, it's just not as good as it used to be, in my opinion at least, I stand leery for their new MMO.