Don't get me wrong, I've been a DC fan my entire life. Also, I REALLY wanted to like this movie, I really did. I couldn't though, it felt disjointed, unorganized, and just flat out made no sense. I don't blame David Ayer though, I really can't. I feel like he had too much pressure from those above him to make a blockbuster to the point where he couldn't do anything right if he tried. That's why I think directors need more freedom: studio interference is usually what kills movies with potential, in my opinion at least.
So... Here's what I would have done differently to make the movie that DC fans not only deserve, but the movie DC fans need:
1. Do more with fewer characters
Warner Brothers really dropped the ball when it came to characters in this movie. DC has always been known for having awesome villains, so theoretically putting a bunch of them together should have been a no-brainer. That being said, they decided to cram in as many characters as possible, and as a result limited character development.
I would have done away with a lot of the excess characters such as:
Katana: Why was she even in this movie? She contributed nothing to the plot apart from being Rick Flag's bodyguard, which he didn't even need given the SWAT team he had accompanying him. Plus, she had literally zero chemistry with the other characters, and not being a bad guy certainly didn't help her with that.
Killer Croc: I get it, this movie was supposed to be full of Batman's rogue's gallery, but there reaches a point when there's just too many people in a movie. Croc was pretty much unnecessary to the plot and could have been done away with very easily.
Enchantress: I honestly didn't understand her character, and I certainly didn't understand her brother Incubus. What were they even trying to do? I can't figure it out for the life of me. I would have gone for a different villain, probably one that's a little more grounded like... I don't know... THE FREAKING JOKER?????
I would have had more of:
Captain Boomerang: Finally, a role Jai Courtney can actually play! Boomerang was hysterical in this movie, not to mention faithful to the way he is in the comics(or so I hear, I don't really read comics much). Plus, he was one of the characters who was actually fun to watch in this movie, unlike Croc.
Joker: DUH! I honestly have no idea why they cut so much of Jared Leto's footage from the movie, he had so much potential to be a great Joker. The guy took method acting to a whole new level (without the downhill spiral of Heath Ledger). I also would have emphasized more of the relationship he had with Harley Quinn, and made it more like that from the comics, being a dysfunctional and abusive relationship. After all, that's how it was ON THE KIDS SHOW from the 90's, where she was actually introduced. I wouldn't have had as many tattoos, though, I feel like that part was just too distracting.
2. Streamline the editing
One of the chief complaints with the movie was that it was too disjointed, especially during the prologue where all of the characters are introduced. For example, a lot of the footage with the Joker felt confusing, such as when he shot a gangster in a club for refusing Harley, as it immediately jumped to a shot of the Joker on a black backdrop shooting at the camera. It made sense of what was going on, but it just didn't look as good as the crew was hoping. That's the other thing, I would have tried to make the film less art-housey. This is a superhero supervillain movie, it's supposed to be easy to follow. Also, the sequence where we see each of the squad's dreams in the final battle with Incubus and Enchantress felt unnecessary, since we already knew what each of these people wanted.
3. A different plot with MORE JOKER!
Jared Leto is a great actor, and it goes without saying that he was underutilized in the movie. He and Waller should have been the only two antagonists in the movie, as they were both very strong characters.
As for a different plot, I think it would have made more sense for the squad to infiltrate Gotham after the city has been taken hostage by the Joker(while Batman was away trying to pick a fight with Superman) and with Deadshot having secret orders to assassinate the Joker. In my opinion, that would have added a layer of complexity to the relationship between Harley and Deadshot. The way this would pan out would be that Deadshot would try to take a shot at Joker with Harley trying to stop him, to which Waller would respond by detonating the bomb in Harley's neck (which Joker deactivated).
After all, I think we can agree that the secret mission to rescue Amanda Waller was just a bad plot twist that didn't help an already boring plot.
All in all, I'm not a screenwriter(yet), so I'm not the one calling the shots, although I hope to be someday. That being said, I've got some high hopes for the people writing Justice League and Wonder Woman to not screw things up. After all, DC fans deserve a good movie that isn't just about Batman.