I did a lot of casual kin centred raiding and 6 man grouping in the late and great LOTRO (not to be confused with the online store that is the new LOTRO-LITE). The experience was nothing like that. Good raids and good group content does feel epic. It brings people together and bringing people together forms the bonds that keep people playing and paying.
There are lot of people out there who are not looking for a simplified but more expensive single player rpg. They have money burning in their pockets for something that alongside delivering a great solo experience also allows them to have fun playing in groups with their friends. These people, people looking for a new long term MMO home, are potentially valuable customers.
With LOTRO essentially dead as a serious game there's a lot of interest in my kinship. But they are looking for husband and wife to easily play together and looking for challenges that groups of friends can have fun together in. Things like Neverwinter and GW2 can be great solo experiences but they're all lacking that extra social dimension.
I'm a big fan of TESO so Zen have my money. I just want the broadest spectrum of MMO player possible to join me so they have even more money.