Originally Posted by The Infernal
No, it would be a dumb thing to do. It would be a needless flashback to characters that barely mattered in the films they were in. Nobody will blink an eye if they are not present in a future where most are dead because it's a simple concept to grasp.
If they want to show what's happened in the dystopian future where almost every mutant died, would it be better to you if they showed other mutants dying, characters who haven't been used earlier?
I can imagine such a secene with Angel, Nightcrawler and Leech, similar to the training program with the giant robot in The Last Stand. Doesn't matter if it's in a blink of my eye.