Yeh I guess. For me and likely alot of people the first 2 are the best, theres a good reason for that. What storlylines can the alien franchise even do before it becomes a muddled mess aka Prometheus.
Human gets attacked by face hugger.
Human colony gets mauled by Aliens.
Government facilities experiment on Aliens then get slaughtered.
Alien, Predator and Human threeway.
Where to go from there ?
I personally would like to see a movie where the crew/colony is aware that there has been something in the past that has wiped out humans but its more on a need to know basis. So rather just a conspiracy. It would be cool too have a discussion about rumours of some alien species that mauls humans but no one really knows of the "Alien".