9. Kept "Spoiler Sequels" Fully Under Wraps
As powerful as Avengers: Infinity War's dusting scene was in the moment, it was impossible for it to carry as much weight as it should've done, because we knew that all those "dead" characters would be returning in a future movie.
And that wasn't just a fanboy dream or wild guess, either: we had factual evidence that pointed to the return of several major heroes. At the time of Infinity War's release, Spider-Man's sequel was common knowledge, as was Guardians Vol. 3, which was being scripted by James Gunn. In addition, Black Panther had just grossed a billion dollars, making a followup one of the safest bets you could place.
But imagine the conversation surrounding the snap if none of these movies had been mentioned? Avengers: Endgame would've been a more mysterious proposition (even if we all strongly suspected that a character as popular as Spider-Man wouldn't just be killed off), and it would've amped up the devastation of the snap even more.
Maybe the MCU could've had movies featuring new characters release immediately after Endgame instead (like The Eternals), and pushed Spider-Man back a year or so. It would've been an interesting experiment to unveil Far From Home, Guardians 3, and Black Panther 2 post-Endgame, but unfortunately, not even a studio as powerful as Marvel can change the extremely long game Hollywood likes to play with its movies.