Avengers: Endgame will go down in history for having one of the best final fights in movie history. It's arguably the best climactic moment from the MCU, thanks to the amount of fan service and creative action that came from the scene. Fans probably wouldn't have taken offense to the scene being longer and it turns out that was almost the case.
However, according to Endgame writers Christopher Markus and Stephen McFeely, it also would have been a lot worse.
Speaking with The New York Times, the writers brought up how the final battle would have had its own three-act structure. There would have been a high point, a low point, and a very low point where the Avengers take shelter from Thanos' army and discuss strategy. If you think that sounds like a lame way to make the conflict last longer, the writers agree with you.
Honestly, the final battle that we ended up getting was pretty great and we can all agree that it was the right call. It will be fun to see a draft of this version of the battle but we don't need to see it in action.
Avengers: Endgame is now showing in cinemas.