I am in the beta as well. It something that is fun, but there is still a lot of things that are odd. Loving the blood dk tanking mode. Rune system had made playing a dk much more enjoyable. Still working out a rotation tho, but as it is now, I can always have a CD running for him.
Loving the fact that they gave rogues a talent to increase there armor. I was getting tired of mine dieing to random little physical damage. Also the recovery this is freaking wonderful. Its going to be nerfed soon I think. Because I can be out and just soloing, and when its cd runs out, I use it and I am back to full health again with out using anything else.
Prot pally has not changed much, and I am really hatting that. Just about every class has had major chances to them, but the huge changes for a pally are in holy (that is really wonderful, healing is much more fun then before) and ret.
Druid changes are alright, nothing too super I have seen yet. Then again, I am only tank with him.