Anything could've been different. That's a fact.
After MOS, what if we've got MOS2 and TB before BvS. Or just TB. But in either case, imagine TB being a prequel with Batman fighting Joker and Harley, or just the Joker, and it deals with the death of Robin in a story showing the confident Dark Knight becoming the distraught character he would become. Then it ends with Zod's message to the world.
What if BvS had a different story? A Red Sun inspired Superman fighting out DKR-inspired Batman, the world siding with either or, almost aggressively. After Superman v Batman with Superman winning, and Batman v Superman with Batman winning, Diana comes in to stop the two and reveal the truth: Darkseid is corrupting the world, including them. Leading to the Trinity fighting Darkseid, defeating him, and ending with two revelations: there are more heroes (cue cameos), but also, Darkseid's influence and nightmares affected every hero's villains. And thus out JL movie is based on Alex Ross' Justice.
Imagine that. That might've been something.
But in terms of what we got, its not bad at all. Its been either great, good, okay or meh. But in the end, the major problems from BvS, SS, and JL were studio interference that affected their running times, story, and those film's directors' visions. This is why BvS wasn't released in theaters but a butchered cut instead, leaving the real cut coming out on blu ray, but in the end, showing that the right editing could've preserved the film with one cut. This is why SS compromised Ayer's vision, that left us with a movie that you could see his hands on partly, but to this day we're wondering if we will ever see his actual version with all the Joker scenes back in. And finally, this is why JL is what it is: because of Snyder's departure via family tragedy, because Whedon could only so much with the 6 weeks he had, and because of WB again, this time being the director if anything, which wasn't a good idea, including the 2 hour run time; you have a movie that does the job, but we all knew could only do so much with its positives before admitting its flaws.
In the end, thats what it is. And what needs to be corrected starting now.