And Marvel and Disney could easily do this again with any other character. Which means that any unsavory or unflattering details that were revealed about them in the MCU might wind up going the same way.
Tony Stark wasn't an a*****e who screwed everything with a pulse! Whenever he spent the night with a woman, they, um, sat up playing chess and discussing current affairs. Captain America didn't get his powers from being injected full of drugs! Those drugs came in the form of, um, vitamin tablets. Hawkeye is good at shooting because he flips houses in his spare time and uses a caulk gu- actually, they'll never care about Hawkeye. Forget we said anything.
This might sound extreme, but the characterization of Loki as a genocidal toddler might've passed muster when the MCU wasn't the biggest entertainment franchise ever, but now that they're thinking long-term, anything that threatens to bring the brand into disrepute is going to be discarded.
Which is a shame, really. As we already mentioned, the best thing about these movies is that, give or take, they're simple. You don't need to have watched every movie in order to understand Infinity War. It helps, but it's not essential, because the movie does such a good job of explaining things (the deal with the Infinity Stones, for instance) that it's easy to play catch-up. It's bad enough that no one dies in these movies, but by retconning story elements in obscure media like the official website (seriously, how many of you have ever read the website), we get a little bit closer to the MCU becoming just like the comics: good, but hamstrung by so many levels of mythology that ordinary plebs are left behind.