In an Empire Magazine podcast, writer Simon Kinberg said Paquin shot a significant subplot for the film, though it was eventually cut from the final release because it didn't "service the main story."
Kinberg said the 10-minute scene would have shown Charles (Patrick Stewart) and Eric (Ian McKellen) on one last mission to retrieve Rogue from "some dark, scary place" to help save Kitty Pryde (Ellen Page).
"The Rogue subplot was originally there because I wanted a mission for the older Charles and Eric to do, something like Unforgiven – two last gunslingers, Clint Eastwood and Morgan Freeman – that kind of a mission for them. I just loved the idea of that. Nothing in the story necessitated that, but just for a lark, I thought it would be a cool thing to see, because we may never see it again, Kingberg said.
"They'd have to get Rogue out of some dark scary place, and that's what happens. It's a really nice sequence, and it'll end up on Blu-ray some way down the line," he continued.
But the Days of Future Past makers decided that Rogue's brief storyline didn't "service the main story."
"I thought it would increase the urgency and the stakes of the plot in the future, but it actually does the opposite, because it makes you feel like there is an answer out there. You think once Rogue gets here, we'll have an unlimited amount of time. The ticking clock that we'd established with Kitty getting wounded and losing her powers... well, Rogue would show up and press stop on the clock. So for all of those narrative reasons, there was this ten-minute subplot that had to go," he said.
Director Bryan Singer told Entertainment Weekly last year that Rogue's scene would have been "extraneous."
"She completely understood," Singer said of Paquin's reaction to the cut. "It's very disappointing, but she's very professional and she knows that stuff happens, particularly with material you shoot early on in production. Films evolve."
You can listen to the whole podcast over at Empire.