It's just not a difficult game to play, FFXI was very VERY involving, but to the point where I think it was a bit too much so. WoW is easy to pick up, but more importantly easy to put down.
easy to put down depends on the person. My brother plays during family dinners, and while watching family movies... I'm sure if you could play on your cell, he'd be playing while working and while in the WC... but for me it was super easy to put down wow, partially b/c when I was playing it was when my pc was broken and I couldn't play ffxi... so I had ffxi to go back to as a reason to put wow down.
It isn't too objectionable though, they had a lot of facets that I wished ffxi had, like a much more interactive environment, and the open edge zones is a big plus. I suppose I could play it now... as I don't have any other game I'm playing besides farmville and other waste of time games on facebook... and wow > farmville. I just can't afford the time or money to put into it while in school... hopefully in a year, when i'm done with school, they have ff14 fixed