It's always a shame that they felt the need not to ruin just Aliens or Predator, but to ruin them both in the same time, and continue to piss on their graves. The people who invented the concept, writers at Dark Horse comics some twenty years ago, at least attempted to create a believable and still very horrific world that could fit both the Aliens and the Predators together. I suppose the AvP PC games have somewhat fit that mold, though I gave up caring.
Part of the entire point of both franchises was to show that we high and mighty humans have no idea what sorts of horrors lurk among the stars, with Alien being about us going out and encountering them, and Predator about it coming to find us. The Xenomorphs tenacity and numbers outmatch our technology and supposedly superior intellect, while the Predators are so much further advanced than we are that we're nothing more than the inhabitants of a game preserve for them.
But no, let's just toss all that aside, make up some ridiculous ancient astronaut story about us being raised by the Predators all along, and have the Xenomorphs already be on Earth. Yeah.