I love the idea of Apocalypse being the major villan in a 4th x-men movie, however I wouldn't take the Age of Apocalypse route (as much as I would love to see it on the big screen) but would rather see it in the main stream timeline already established by X1, 2 and 3. I was disappointed with alot of the outcomes of X3 and I would use an Apocalypse storyline to try and correct some of it.
Although I haven't gotten as far as the ending yet in my though process, I would like to see an introduction along the lines of the following:
- We are introduced to a dark future where we see scenes similar to that of the danger room in X3. Introduced to Cable (although not specifically at the time, rather just a mutant fugitive), introduced to Apocalypse (although also not directly, rather through phrases such as "its Apocalypse's horsemen". The desperateness of this future brings about cable to use one of his mutant powers - time travel [yes I know not actually his mutant power, but the movie series so far hasn't been that faithful either]. He travels to the present day in an effort to avert his dire future.
- In the present day he gets involved with the X-Men, where we learn that the supermutant Apocalpse was created during the events of X3 when Jean disintegrated all those mutants and soldiers they didn't actually die but were merged with a the mutant En Sabah Nur to create Apocalypse [yes I know also an adaptation of the comics, but thats what happens in comic book movies]. If any of you have noticed yet I'm trying to combine the "Cyclopalypse" story line and maybe a hint of "Onslaught". Basically what has happened is that i've undone allthe deaths in X3 that were due to Jean, the bodies and minds were unintentionally merged with this mutant. Perhaps the man lying in the hospital bed and due to Xaviers enormous psychic ability managed to utter those words to Moira at the end of X3.
- In order to preserve the peace the x-men must destroy Apocalypse by seperating the merged bodies and killing him when he is at his most weakest, which is only possible by the aid of the most powerful psychics and at Apocalypse's weakest point. This brings about the relevation that Cable is offspring of Jean and Scott, thus Jean is still alive and that Scott will eventually be saved. However just sererating the merged bodies is not enough, Apocalypse must be prevented from continuing his existance as he will eventually rise to power once again. In Cable's future he rises to power after the merged bodies of X3 are seperated and the weak En Sabah Nur is allowed to live - which is the greatest mistake. So then the moral issue of essentially murdering the weak and confused child that was the essence of Apocalypse (En Sabah Nur) befalls the x-men.
This was as far as I got and I obviously haven't worked out details, such as Jean's survival or why she is no longer evil, but my hope was that it would be her battling to seperate the merged from Apocolypse from outside and Xavier battling him from within (cue scenes similar to that of the Astral Plane). There is probably a lot of materal to cover for just one film, but i'm sure if it was given some good script writers and a decent screen time (as opposed to X3's dismal 103 mins) you could get it all in and perhaps have some sort of story in this one unlike X3's problem of the story placed behind the special effects.
I personally thought that this was the best way to undo the deaths that happened in X3 while at the same time trying to remain as true to the comic book as possible.
So c
riticise if you wish but i would prefer comments such as "thats not a bad idea but could use some work" 
Perhaps you guys have another idea that you could add to the plot or change something that I have written.
Remember though, I was trying to make a story that would suit the big screen, be realistic enough for audience unfamiliar to X-Men (not too far fetched - if that makes sense!) Staying true to the trends and themes set in the first three movies yet not being totally untrue to the comics!
