I can see Fox pulling and Aliens and making the sequel more action packed
I hope they can resist that urge. Of all the criticism we've heard re: Prometheus, I don't recall too many (intelligent) people saying it would have been better if it had more 'pew! pew!'. From what I'm reading, most people seem to wish it was just more logical and that it would deliver on the big promises that it makes.
If they can make an artful, intelligent and terrifying sequel to Prometheus, they'll be heroes. If they make a standard action-fest, I think, it'll be the last straw for many people. Just my opinions, of course.