I wasn't terribly impressed with the Zack Snyder cut of Justice League. The real problem with Justice League isn't the lack of supporting scenes, it's the fact that it has Death of Superman jammed into the middle of an origin movie where it doesn't belong.
To that end, I'd really like to see a cut of Batman vs Superman where Superman doesn't die at the end of the movie. It would fix so many things.
You'd end the movie with Batman and Superman having grudging respect for each other, and along with Wonder Woman, you have the core of the Justice League together, with momentum, instead of having to spend half of Justice League moping around getting the band back together.
You get nearly an hour back in Justice League to give the other heroes their backstories, and maybe introduce some more villains for Justice League 2.
Oh yeah, and you probably GET a Justice League 2.
And you get to do Death of Superman properly, late in the series, ideally as the last movie in Henry Cavill's contract. That way there would be actual uncertainty about whether Superman was coming back, plus the audience would be a whole lot more invested in the character by then. It would have impact, and the outcome would not be a foregone conclusion.
And then you get to bring Superman back, and have it carry another whole movie.