I'm a little late to the show, but I'll give my two cents now that all four forms have been unveiled.
I like the new forms all in all and have my favorites already picked out; it's going to be a matter of compromising my hair color to get what I want. Taurens have it a little easier because they can change everything but their faces at the barbershop once this goes live. We night elves will have a tougher time trying to match a new hair color to our existing skin color.
What excited me most was the fact that bear will close their mouths. How many times have I tanked Naxx and said to myself, "Who you calling a slack jawed... oh yeah".
The only thing that I don't like right now is the cat feet, they look like amputated stubs with claws sticking out. It works for the bears, not so much for the cats. Cats should have some differentiation between their toes even if it ends up just a modification to the skin.