He was likely killed off in Age of Ultron because Marvel didn’t fully own the X-Men at that time. But now that they do, there shouldn’t be a reason why he couldn’t fully return to the MCU.
Since Wanda is likely (hopefully) to return to the MCU in one of the upcoming films, it would be great to see a variant of ATJ’s Quicksilver from a universe where Wanda died during AoU’s events but he survived, and would be all the more protective of her as a result. It would be a great and heartwarming moment to see them reunite on screen, especially since we’ll also likely see Wanda reunite with Vision and her kids as well, setting them all up as leads for the incoming new marvel universe-focused Saga.
Plus it would be worth it to see Deadpool make a snarky comment about Kraven’s failure that resulted in ATJ’s return.
Any thoughts?