I powerleveled people/groups in FFXI. This is something that is possible to do in most grouping MMO's so there is really not a lot of proof that it kills grouping. They seem pretty intent on improving group play with the linking system, xp chains, and more party areas they have planned.

I don't see this as a big deal, you still have to have someone willing to powerlevel you which not everyone will have. There were still plenty of real groups in Yuhtunga/Yhoator Jungle despite all the people who powerleved people/groups there.