Oh gosh... If this thing is anything like Mass Effect, I believe it will be unbearably awesome! I love that game and greatly enjoy it still.
However, I really hope you get to play as a marine. I believe it gives you greater flexibility and will allow for a better story and experience. I pray they allow a great deal of weaponry that is upgradeable. That will be a dream come true!
As for not including yautja, Im actually pleased with that. While I am a die hard Predator fan, AvP combo does limit what can happen. While it does allow new opportunities for great stories, it also constricts what can happen as well. Anywhat, I hope that in the future they make a Predator version of this as well that includes stuff aside from hunting humans and aliens. Gimme some other beasts!