I thought Prometheus was great, especially after the fairly pointless Alien Resurrection, the shitty AVP movies, and even Predators- which actually looked promising and had Robert Rodriguez behind it and had so much potential to be badass but it just ended up pretty meh. Prometheus though was a huge step in the right direction. I know not everyone loved it and had issues with it but it at least had some ambition to be different, and it had a lot more substance to it than just a prequel to the tune of "here's some scary shit that happened before the first Alien." It was much better than that and it kind of sits within a league of its own, and I really do hope we get a separate trilogy out of it. I know there's talks of it but you never know. I'm really curious to see where they take it.
But as a franchise as a whole it has so many directions it can go. We can definitely get some more movies set in the Prometheus universe but in my heart of hearts I just want one more shot at seeing Ripley's story and where it goes. It can't just burn out with A:R. It just can't. We got John Mclane back, Rocky back, Rambo, and Indiana Jones- hell, the original cast of Star Wars is making a comeback with another movie. I want a 5th Alien movie with Sigourney Weaver, damnit! Just one more.
Also, I wouldn't mind another Predator or AVP movie...even if they have to reebot AVP. I think the biggest mistake of AVP was setting it in modern times. First in Antarctica and then in some nowhere suburban town. WTF? That's such bullshit. If they can make it with colonial marines and give it an Aliens type vibe it would be amazing. I always thought it wasn't just aliens and predators, but MARINES included that made the concept so interesting, and that's what made the first two PC games (and to a lesser extent the more recent AVP console game by Sega) so good. Because, shit, marines are trained to be badass killers, so they're appropriate to set up against the two snarling extraterrestrial beasts. Um...research scientist? No. Fucking PIZZA BOYS? NO NO NO NO!!!! It's really simple, they really fucked it up. Get me an AVP movie with the aliens, the predators, and the MARINES, set in the future.