I think before it was less being literal and more referring to the franchises it was representing.
Initially, when AVP started, it was essentially bringing Predators into the 'Aliens' franchise, as that was the popular film spawning a whole host of stuff at the time. After that Alien went back to being 'Alien' as a singular title for the franchise, then in 2010 we had 'Predators,' though Predator 2 did have plural Predators in it.
So Aliens vs Predator was bringing the Predator franchise into the Aliens world of the future with space marines etc.
Though the first video games such as the Jaguar one, SNES one, and the Capcom arcade were all 'Alien vs. Predator,' until the 99 PC game.
Then we had the Anderson film that had them both singular, which they changed back again for Requiem as Strause Bros. liked 'Aliens' as a movie.
Both the older and the current logo styles have used Alien vs. Predator and Aliens vs. Predator
Alien vs. Predator has been the more common one in recent times. As far as 'Predators' goes, only that movie and the media related to it have used that instead of 'Predator.'
This is the very first time we've seen 'Aliens vs. Predators' used, and it seems to just be literal in this case, but yeah, it does flow nicely.