According to ComicBook.com on Monday, sources revealed in an interview with "X-Men: Days of Future Past" director Simon Kinberg said that he and original "X-Men" director Matthew Vaughn had considered Cable to be in the Marvel Cinematic Universe. First off, Kinberg talked about the reason behind Wolverine's mission to be sent back in time, as he felt it was the most logical, reflexive thought to do so. After all, he was the only known surviving member of the mutant clan that could rendezvous with himself during the Nixon administration.
Kinberg also went on to say that during the course of choosing what Marvel character to send back in time. He also mentioned that he and Vaughn figured they weren't that smart initially to consider Wolverine as they were thinking along lines of sending back the Cable or Bishop characters. Perhaps even some kind of newer character in order for them to take on an older role, sending him/her back in time, and then making the youthful actor they use for that version as the "new young actor."
During this thought process, they were figuring who could they cast that had the mutant ability to never really age much, was a popular character in the franchise, and then as a result, Wolverine was the one that obviously stood in the forefront to fit the standards. Though the only challenge for Logan would be to show patience when encountering Professor X's younger self. As the Wolverine had said, "Patience isn't my strongest suit."
Anticipation by fans for Cable have long been running ever since news revealed that Jeff Wadlow was working on an "X-Force" script for 20th Century Fox. It's even possible that Cable could end up finding himself premiering in another movie before an "X-force" film.
For those who will be okay with not seeing Cable in "X-Men: Days of Future Past" and just seeing the next best thing, Bishop, feel free to see the movie in theaters in which the film is currently running.