According to the info released about 10 days ago about titan, it will be hardcore orientated :
http://titanfocus.info/_/news/projec...3-and-more-r65
They want to make it into an eSport, like WoW was never able to because of the constant balancing of classes and abilities (pvp or pve. You can argue wow PvP is an eSport, but ... its not). You can't nerf stats every week whenever the player base QQs if you make a game an esport. Immagine SC tank and marine damage changedf whenever a zerg player QQ on forums. Doesn't work like that. So there will be much less nerfs, and much more stability.
When you say eSports, of course people can play it casually. But at least the ones who do play casually won't impact the hardcore player base (ie: no nerfing all the time to make the content doable by everyone. there will probably be leagues or something along those lines. Depends how much PvE / PvP it is. I don't even know if there will be bosses or whatnot).
Wow , by design has a model where its (arguably..) hard the first weeks, then nerfs kick in, whether they be blanket (ICC, DS etc), or individual and boss specific (ToT).Titan, from the little info we have at the moment, will not be like that. (yipeeeee)
WoW will be here to cater for the casuals, as it is increasingly doing so (as explained by posts above, Quarterly call followed by nerfs, and LFR etc), even though casuals still can't interrupt an add and move out of green on the floor.