I wanted a Dark Ranger more than a Demon Hunter to be honest... but lets hope they announce 2 classes instead of 1.
I don't know if anyone else noticed this:
http://store.picbg.net/pubpic/3E/8F/...c1ece43e8f.jpg
It's either a tease or an actual hint that Demon Hunters are coming sooner or later. Also with a Burning Legion expansion that we are all expecting it to be after MoP I think it's pretty safe to say that it would be something along Dark Ranger or Demon Hunter.
I guess a Hero Class like the Death Knight with unique background story.
All races can be Demon Hunters though Night Elves are most common next to Blood Elves
"Any race can become a demon hunter, though almost all demon hunters today are night elves, with a minority of blood elves. The tradition of demon hunters arises from night elf history, and almost all demon hunters are night elves. A few blood elves have made the pledge as well, seeking revenge for the destruction of their home.
Humans can also be demon hunters. some of these demon hunters can be found guarding Mount Hyjal with the help of fellow night elf demon hunters.
Demon hunters in other races are rare, but some exist."