Originally Posted by Dark Raven
Unless whoever comes from the future comes to a time before X3 when they were either still alive or powered. That way it won't ignore X3 as such, but just would be taking place before that happened. However, once the timeline is played around with, things would change and X3 might never transpire. I don't think the audience would have a problem realising that it's at a point in history when those characters are still alive and not that they've suddenly been resurrected, especially if the future traveller looks at where to travel back to and picks that period.
Okay...so you're suggesting a time-jump to a period in the X1-X2 timeframe. So how does the 60s setting of First Class factor in? That would need another time-jump.
I have no problem with your suggestion. Or, for that matter, with seeing the return of Xavier, Jean and Cyclops, and a repowered Rogue and Magneto, as long as there is a logical explanation (hopefully one that's clearly stated or is very obvious!)