It has been established that Hicks has been killed off in Alien 3. However, that decision has been met with a lot of criticism due to it being the abrupt ending of an iconic character. Alien 3 has been criticized not for its dark tone, but for it being a mess when it came to the narrative and the skout structure. The assembly cut has smoothed out some of the issues. However, David Fincher has disowned the movie and refuses to do anything to put together an actual director’s cut.
One theory that is looked at is that Hicks was awoken from stasis to fight off an attack. During the fight, he accidentally ejected Ripley and Newt from the ship. There are issues with the problem. If Hicks was awoken from stasis, then who’s body was crushed on the ship. There is a lot of speculation as to how Neill Blomkamp is going to resurrect Hicks, especially since the time between Aliens and Alien 3 isn’t enough to age them more than 20 years.
How the mystery unfolds remains to be seen until the movie is finally released.