I don't think that it's the end of boxing but with the way raid/dungeons are being designed it will probably be quiet tricky to box them. It's not that Bliz hates boxers but rather they're trying to create interesting/challenging content which usually involves movement/vehicles/new mechanics based play. I've accepted the fact that mostly likely future content won't be 100% boxable; I plan to raid that content with one of my many toons 1 boxing. As the previous poster said.. single boxing is still fun if you get a good group. If it ever gets to a point that all I can do is run old content with my box teams then that would be time to think about packing it in.. so far still having fun though.