Ive noticed COA has been pretty much lag free since Saturday morning aswell
Just into 97 myself and playing through Spires of Arak at the moment, 3rd q hub in I think. Terador (?) is probably my fav zone so far - had some real fun trying to place where I would be if I was in Terrorkar in Outlands
Really liking it from what Ive seen at the moment - not sure there will be much replayablity mind you but as there will be a new expansion in a year (ha) I think I might be alright just concentrating on the horde hunter and then play some alliance mage in a month or 2.
I've also noticed that peeps dont move from AoE effects etc, but its the same every expansion as they get used to facerolling and letting healers cope - expect damage and the like to be 'tuned' as Blizz crumbles to the whiners.