Also, reduce the amount of slow motion. Reduce grey scale. Actually make Batman and Superman different characters like they did in the comics(both of them were literally just the same guy in these movies, except Bruce was a little angrier).
When you establish parts of the story that are genuinely interesting, like the mental illnesses of Bruce and Lex, actually delve into them and give them focus over "I HAVE TO GET TO THE NEXT GREY PRETTY SCENE."
And Cavill's acting. For God's sake, when a man who's driven by protecting innocents to the point that he dies for it sees dozens of people die with his inability to stop it looming over his head, give him facial expressions that aren't the one pouty "I smelled a fart" face.