I concur with this... I like seeing the start of the violence and gore and leave the rest to my imagination. I do think it'd be hard to comprise a movie of these to characters because in Predator 1 more so than 2... You like the humans and root for them, but you kind of like & root for the Predator and it's has more of an action "suspense" feel to the movie. Where with Alien you hate the Alien and root for Ripley, Bishop, Hicks & co and want the Alien/s dead and killed because they are so damn scary and in those movies. In Alien & to Less of affect Aliens, the suspense is more "thriller/horror" suspense, imo... I remember the first time I watch Alien; I had to turn the volume off... The suspense with the music was scaring the hell out of my 11 year old self! So it'd be hard to manage the tension of the Alien movie with the action of the Predator whilst give human characters the time to make you want to like and root for them...
Basically, I think they should have done Alien 1 type movie again with a small swam of Aliens terrorising a small team of Astronauts after 2 or more team members get attacked by face huggers after investigating a mysterious vessel. Then have a Predator sneak on board the ship and try to Cap every one in the ship, including the Aliens... With scenes where the Predator would save a Human/s from an Alien, only turn on the human/s to claim their skulls. It would be great because you'd be like, what's going to attack them the Alien or the Predator... Then the ending could be a mix between blowing the predator out of the air lock, taking his nuke and use it to blow up the ship with the alien in it whilst the survivor would escape in a pod, doomed to be stuck in hyper sleep until the sequel... Done!... Just pay some decent half name actors to star, get Cameron or Scott to direct (thrown an arm & a leg at them) and get a quality composer and Bob's your dad's brother! Cinematic History!