Best analogy I can offer is comparing a comic book to the Game of Thrones books, both the positives and negatives of each.I'm trying to determine what kept me playing WoW a lot longer than D3. Essentially, they're the same games: loot hunts. You kill the same shit over and over and hope the thing you want drops. Was it the better drop rates in terms of hours played? Was it the raid lockouts mitigating burnout? Was it the social factor? Was it PvP(for some, not me, I suck at PvP)?
Just writing this makes me want to play WoW again. And if it wasn't for the whole host of negatives with cat herding(sorry, I can't play an MMO without raiding), I just might.
I keep getting the MMO itch and a quarterly free week of WOW and dailies and LFR are enough to remind I'm not interested in it. A month of TESO also really killed my MMO desire, at least for a bit.
It'd be awesome to have a 3D casual D3 like MMO with a tad more depth.