HIG, you're comparing apples to oranges. Freddy vs. Jason was a spoof on a horror movie at its best, since no one has taken that genre seriously in what, 15 years? Alien vs. Predator, on the other hand, is a classic arcade game, somewhat referenced in Predator 2 (with the xenomorph-like skull on the predator ship) and which is not nearly as stupid. There's more chance for a plot anyway.
As for Alien: Ressurection, the whole idea of a "hybrid" is somewhat messed up. The aliens in that series, refered to as Xenomorphs in several points, already take on certain attributes of the host they grow in. The one in Alien 3, for example, grew in a dog and was more canine in the way it moved (at the cost, we assume, of some of its intelligence). So mixing that with Ripley should have produced your "standard" alien.