SPOILERS FOR X-MEN MOVIES! SO MANY SPOILERS
Time travel movies aren’t easy to get right. Be too fastidious with the science and you risk alienating your audience, ignore too many of your own rules and you risk distracting them from the plot and characters. Most continuity issues within Days of Future Past itself come from it being a prequel, not a time travel film. In fact, the film actually handles its time travel elements better than most, it just makes casualties out of the earlier films in the process.
So somehow preventing Trask’s death and having mutants save the President (from a scarier mutant) means that the dark future inhabited by genocidal Sentinels never happens. One of the worst narrative travesties occurs when the Sentinels are introduced. In 1973. Which would mean they would have been hunting and killing mutants, growing more and more advanced with every upgrade ever since 1973. All the way up to the dark future time period. 50 years of mutant slaying. Odd that no-one mentioned them in X-Men 1-3 or the Wolverine movies. I guess they weren’t very good at their jobs until recently.
Plot holes like this are a symptom of Prequelitis. Just ask George Lucas. Telling a prequel story without altering your beloved characters or worlds is tricky. Other problems are plot strands that are simply dropped from the other films without explanation. How is Professor X alive? Where did Kitty Pride get her sweet time travelling powers and would they not have come in handy earlier? Why is Magneto fighting the good fight and more importantly: when and how did he recover his powers? None of these issues really matter when your intention is to retcon these films into oblivion.
Until now, the X-Men universe had produced films of drastically varying quality, but through all the highs (First Class, X2) and lows (Origins, X3) one thing that the filmmakers cared about was continuity. Yes, even Brett Ratner. X3: The Last Stand is a misfire on many levels but it completes character arcs (however poorly) from the first two movies. It is in turn legitimised by The Wolverine (2013) which uses Jean Grey’s death as an important part of Logan’s journey. X-Men Origins: Wolverine was a mess of a film, but it honoured the films that came before and tied Wolverine’s Weapon X flashbacks from X-Men and X2 directly into its narrative. When it concluded it led satisfyingly straight into X-Men.
These films all respected the fact they were part of something bigger. They cared that these characters existed in the movies before and after the one they were making. The very premise that Disney’s Marvel Studios’ success is built on.
On one level it’s pleasing that the contentious events of X3 never took place. But if the price is also wiping out the events of every other X-film (save First Class, its 60’s setting excludes it from time travel tinkering) then I’d say that price is too high. As film fans, we enjoy connecting with these characters and watching them go through trials. They grow, they learn. Not anymore. None of those movies ever happened. Those stories have been erased. Whatever events brought us to the happy, shiny ending of Days of Future Past, we are not privy to them. One could argue we don’t really know these characters any more.
Days of Future Past could possibly have weathered the storm of the aforementioned continuity errors. By ignoring certain elements to tell their story the filmmakers might have been able to get away with it. But did they have to eradicate every other X-Men film in the process? Killing the perceived weak to ensure the survival of the strong?
Magneto would be proud.