Love it or hate it, good or bad, Prometheus did more to rejuvenate interest in the franchise than any entry since Aliens, and made a ton of money to boot. Your saying it didn't give anything to the franchise is way off the mark.
I didn't say it did not contribute anything to the franchise, I said it didn't deliver the stuff it promised before release. Just because there is a colossal hype to it's sequel I can't be blind to it's many faults. That and it's too bleak in comparison to previous Alien films.
Regarding Predators I stand firm on my opinion. Everything about it was generic. Beside visuals, game planet and creatures I can't find strong points in that movie. Even characters were uninteresting compared to P1 and P2. With or without it Predator franchise suffered enough because of AvP. And the main reason why I bash it so much is because of Rordriguez, because he thought his film would be superior to P2. We saw how it turned out. Back to Alien 5
Even though I like Neil Blomkamp's movies I find it difficult to believe with retconning whole 2 movies will help the fifth installment. I am afraid more mess is on the way, Time will tell.