I think when Cata hits, the playerbase will suffer a bit. Not only that but the main things we enjoy ingame will be improved only to an extent that we'll find feasible.
So the changes I think will come to the reconsideration of the staff and we will see a downturn in the players. We'll know for sure when the actual open beta hits but for now we speculate and only hope that is this not forthcoming..
I see no other outcome though :-\. I love WoW and play it.