Only way for me to fix it after The Predator would be standalone movies that happen before The Predator. So you don't have to deal with all the stuff they established in that movie.
History is full of conflict in warm parts of the world. Why not throw one or two predators in one of them and done.
Biggest mistake they can do now is overcomplicate it to make the new stuff work. Predator works with simple, small scale plots. Marvel style cinematic universe, big scale world invasion plots, battle suits and all that shiney big spectacle works for superheroes and Star Wars, i don't think it works for Predator.