Overall, there have been some major missed opportunities within the DCEU. Major storylines and characters from the comics have been introduced and rushed, instead of just focusing on one cohesive story. If WB wants to set up a shared universe, then there needs to be a vision set forth by the writers and directors that has a clear path and endgame. Many decisions have been made in reaction and retaliation to Marvel, when DC needs to focus on DC. Instead of making a Batman vs. Superman movie to compete with Captain America: Civil War, make a solo Batman movie and a Man of Steel sequel that are released that year and set up this major conflict between DC's two most popular heroes. Patience is a virtue and if WB hadn’t tried to do things the opposite of Marvel, then maybe we would have had a few more movies to get to know these heroes and by the time they joined to form the Justice League, it would have been worth the wait.

No Lanterns...No Darkseid

As far as characters go, two that absolutely would have given more depth to these films is Green Lantern (Hal Jordan or John Stewart) and Darkseid. Bruce knows that something darker is coming to Earth and has even seen the Omega Symbol in a vision, but still we do not see who is pulling the strings behind Steppenwolf and this possible "Knightmare" future. These characters would have been easy to connect and frankly a little too convenient for the studio to just forget about. 

What Could Have Happened: More Lanterns could have been included in the History Lesson, and we could have seen where the ring ended up after its owner was killed by Steppenwolf. When Steppenwolf first arrives in present day, Abin Sur could have been there to meet him and try to stop him only to fail. This would have been the perfect time for the ring to fly off to find the next protector of Sector 2814. Insert a scene towards the end of the movie where we see the ring approaching Hal Jordan or John Stewart, only for them to put in on and there is a flash of green, the end.

Another option is after Steppenwolf is defeated and boom tubed out of the conflict, we could have seen him returning to the lair of Darkseid, and we soon come to learn that Darkseid has imprisoned the current Green Lantern. In the same way that Joe Mangienello was introduced as Deathstroke, the scene does not need to be lengthy, just enough for the audience to know that Green Lantern is out there and is going to be played by A-list actor, (Insert Name Here). This would have been a great way to set up this massive universe and give some die-hard fans resolution as to why one of their favorite founding members of the league was not joining the fight right away. 

How to Fix It: Luckily, WB still has an opportunity to do that in a post credits scene in Aquaman, or in a future DC film (if they still decide they are going to move forward after the box office disappointment that is Justice League). Having Green Lantern being taken prisoner is really the only scenario I see working at this point, just because if he wasn’t taken prisoner, then it is very hard to believe that he wouldn't show up to stop a major threat from destroying his home planet.

Give The Justice League A Signature Theme Of Their Own

Can you recall how you felt when the Avengers first assembled at the Battle of New York with Alan Silvestri’s renowned score playing in the background loud and proud? For me it was chills and the realization for the first time these heroes were coming together after being teased for years. You cannot hear that music without think of The Avengers, and this even more prominent with the recent release of the Infinity War trailer. As much as I love Danny Elfman, his score for Justice League and Avengers: Age of Ultron was underwhelming and honestly not as loud and prominent within these films as they should have been. Also, if Danny Elfman thinks that he is getting away with reusing his score from Hulk in those Flash's Speedforce scenes, swing and a miss. 
 
What Could Have Happened: The themes from Wonder Woman and Man of Steel should have been a point of focus in the fight scenes and especially during Superman’s resurrection. The Justice League needed that gathering moment similar to when the Avengers first assembled. As much as DC was trying to set themselves apart, this is one thing they should have taken some advice from. Write a score that is going to always connect the audience to these heroes for years to come, and let them know that when this song plays, s--t is about to go down. Also, let's settle on what Batman's theme is going to be. Is it Junkie XL's drums and percussion instruments creating a dark setting for his scenes or is it Elfman's well known Batman 1989 theme that can be contorted and adjusted any way they see fit? At this point if Ben Affleck is going to stay, then keep the Elfman theme. It has already been connected to the character and having the previous Burton movies as semi-canon isn’t the worst thing that can happen. If Affleck is out as Batman, then I say go with a new theme for a new actor, and let that be the theme for him moving forward in the DC universe. 
 
How to Fix It: As memorable as John Williams’ Superman score is, Hans Zimmer did a hell of a job with Man of Steel. After hearing the new theme in the first trailer, it immediately tugs at your heart strings, but at the same time is exhilarating and gets you excited to see more from the Superman. I thought the trailer for Justice League with Clark and Lois in the beginning with the theme slowly playing in the background, was genius. Not only did it prevent spoiling Superman for the movie, but it also tied together what had come before and the history between the two. These little moments work so well, so why abandon it? So many people fell in love with Wonder Woman and her theme when she first blocked Doomsday's blast aimed at Batman, only to reveral herself in all her Amazonian glory. If Warner Brothers wants to focus on beating Marvel at something, let it be the music. Other than the theme for the Avengers and maybe Thor, there hasn’t been a theme for each character established that is indistinguishable from the other films. Some of the scores have been very generic and this is one area DC can capitalize. You already have great themes for two of your characters, so keep that momentum going in the right direction for characters like Flash, Aquaman, and Cyborg. 

The Death Of Superman

This was way too premature. The audience needs time to care about the character of Superman so much that the loss of the Earth’s “savior” from Krypton is devastating. By having half the world hate him in Batman vs. Superman, the effect of his death is lessened even with the ending montage in the movie.  It is completely possible that after shooting the majority of the film, Zack Snyder and Warner Brothers realized that Superman was just a little too dark for most people’s taste. The way to salvage that would be to kill Superman and basically soft reboot the character to which audiences will respond better. If anything, they hit the nail right on the head with the “new” Superman, as he is hopeful and optimistic and the Superman we have been waiting for since Man of Steel.
 
What Could Have Happened: Why not save Superman’s death until Man of Steel 2 or a Justice League sequel? The audience was not invested enough emotionally to this version of the character to kill him off, so keep him alive for the time being and giving more than 15 minutes of report with the rest of the members. Thus would have made the team more cohesive and brought them closer together. Doomsday should have looked substantially better in CGI and design, and could have had a much cooler set up rather than just having Lex cook him up in a mothership and let him loose on the city. Doomsday could have been a failsafe instituted by General Zod in the case of his death. Once Zod dies, the mothership could have been programmed to start the birthing process of Doomsday with one intention and that would be to kill Kryptonians. Since Zod knows that if he dies then Superman would be the only Kryptonian left, then Doomsday would solely focus on killing him. Or if they really wanted to stick with Lex creating Doomsday, then have him be programmed to hate Superman. This could of worked in a variety of ways, and unfortunately the route they took was not a great one. 
 
How to Fix It: No fixing this one. Superman’s death weighed over Justice League and forced the plot to rely on this and his resurrection. It shouldn’t have taken them three films to get a Superman we enjoy seeing. He is pretty depressing for a majority of Batman vs. Superman, and an opportunity was wasted to show the contrasting worlds and personalities of Superman's bright, all American way of looking at life, opposed to Batman's dark and melancholy point of view. The only way to move on from this is focus on the Superman you have created in Justice League, and make sure future directors keep this tone. We need to believe in Superman as much as he claims to believe in us, and that means having hope, above all else. Let's hope it's not too late.