The Predalien is something of a complicated subject. It truthfully needs to maintain it's Alien-like quality, but by completely unique in it's own way at the same time. It's something that will defenintly strike a heavy blow to AVP2 if not pulled off properly.
It is essentially a Xenomorph, so it needs to keep the essense of an Alien about it, but at the same time, have certain traits normally unique to the Predator. It's a very fine line to walk, as you can either make it more Alien, & basically turn it into a Drone with mandibles, or you can give it more Predator characteristics & then it would no longer seem like an Alien. As I said, it's a delicate balance, but if they can get it right, the Predalien should hopefully turn out to be something quite remarkable.