Despite the accusations of formulaic film-making that regularly greets a new MCU movie (usually from the area of the Internet populated most heavily with DCEU fanboys turning everything into a war), Marvel Studios have thrown a lot of curveballs since their shared universe kicked off.
They messed with the genre of Captain America: The Winter Soldier to the extent that it was more like a 1970s political intrigue thriller than a comic book movie, they turned Ant-Man into a comedy heist and Doctor Strange became a glorious acid-soaked trip. They've shredded established storylines like Civil War and Age Of Ultron, reinvented characters entirely and skipped over moments that fans of the comics would have taken as guaranteed.
In other words, it's pretty fair to assume that expecting Avengers: Infinity War to be a play-by-play remake of the Infinity Gauntlet storyline is entirely foolish. It's far more likely that the Russos will use the story as a framework while still seeking to shock their audience with a healthy injection of left turns. And that doesn't just mean deviations from the source material either: Infinity War represents an opportunity to completely screw with fan expectations, and hopefully Marvel will take it two-handed.
If it's going to "change everything", we can probably expect some serious bumps in the road...