If Fox has taken pains to maintain one continuity, why are there still inconsistencies? I mean I get that different people worked on different projects, but as the Overseer, Fox would have had to step in at some point and say "you can't do that because we already did this." I mean why even allow Beast to be in First Class if it messes with the continuity set in X2 and X3?
And like I said, Time Travel is the perfect cover up because it works within the boundaries of the story. The fact that there's a comic based on the same idea is what makes it allowable, and I'm not saying they have to, but the fact that so many people were outraged about how Jean, Cyclops and Xavier died in X3, you have to wonder if they would consider bringing them back somehow since those are the characters that can and should lead the franchise. X3 was pretty much a shot in the foot because they limited themselves on what they could do if they ever wanted a X-Men 4.