Warren was very proud of who he was during the horsemen storyline and that was partly the reason why he was a horsemen. Which is the exact opposite of the animated version. The movie kinda told Warren's story arc but with Magneto. He goes into depression, is the final horsemen, turns on Apocalypse, and helps the X-Men. It's like how DOFP replaced Kitty with Wolverine.
I wouldn't say he was made into a joke. But rather he became underutilized due to being basically redundant with the presence of Sinister.