It really just depends. I don't personally like the idea of Amanda being a character in the new film because if not done properly that can very well damage the film series as well as the game series. Not to mention at that point what's to stop them from adding other characters from other games.
I know I'll probably get shredded for this but personally there are aspects of the ACM game that I liked and felt would be a great plot for another film. I liked the idea of going back to LV-426 to ascertain what happened. I liked the idea of another platoon being in the vicinity and being rerouted. It could be that when bishop was getting the other dropship from the sulaco he sent out a distress beacon requesting help. I liked the idea of a high security wey-yu team (mercenaries) being put in play to assist with containment teams and science teams. I liked the idea of returning to the original crah site of the derelict.
I mean... there are so many aspects of that game that could be put into another film.
Now don't get me wrong. I'm not saying we should do another full blown marines vs aliens film. As entertaining as it would be... it's been done before. But maybe a team locating the sulaco and being killed by the wey-yu forces. Wey-Yu teams have already located the ship and boarded it. During this time security sensors awaken hicks. He goes to the armory to gather weapons and before he can intervene with the forces. The fire breaks out in cryogenics. While he is putting the fire out the ship is boarded and he is captured. The computer loaded the remaining tubes into the EEV and ejected it to protect the crew. Wey-Yu security teams scuttle the sulaco while science teams are examining the derelict, the egg chamber, and the destroyed atmo.
Maybe have a small group of marines that survive and land on LV-426. While sending out their own distress beacon they begin trying to locate members of the sulaco and begin scouring through the wreckage and debris of the ATMO searching for evidence of what happened. Then they run across the wey-yu forces again as well as a few aliens. Either they manage to find a survivor of the sulaco crew "hudson" who was spared from death because he got away in the underground tunnels before embryo implantation. Or they manage to free hicks from wey-yu custody. It is then determined that wey-yu has been after the alien species for thier bio weapons division. While doing reconnaissance on the science team at the atmo they learn that the explosion didnt kill all the aliens because several where underground in the hive below volcanic rock. Now it's a mission to destroy all traces of existence.
While they're at it maybe bring in an alien transforming into a queen. Yes I know it does away with the egg morphing theory but personally I liked the queen. I think they could still tie in egg morphing though. Such as if there is an abundance of prey an alien morphs into a queen so that eggs can be mass produced in a short time frame. Without an abundance of prey there isn't a need for an egg layer therefore the normal process of egg morphing is used.
I feel this would make for an entertaining film that could merge all story lines together. May not be a perfect merge...but it's still a merge.