After watching the third Batman vs Superman trailer, I have done a lot of thinking about Doomsday, and why WB decided to have him included in the trailer. I love Doomsday because he is one of very few things that can kill Superman. When I heard Doomsday's roar, I went to the edge of my seat. After all of that, I screamed "No!" At the time, I felt as if Doomsday was a horrible choice for the 3rd act. I've done a lot of thinking, and I came up with the conclusion that Doomsday needs to jump start the Justice League. It will show our heroes realizing the mad man that Lex Luthor really is for creating such a monstrosity, and we, as the fans, need the Justice League to come together before Justice League Part 1 hits theaters.
At the beginning of the trailer, we see Bruce telling Clark that "Maybe it's the Gotham City in me. We just have a bad history with freaks dressed as clowns." The obvious thing we get out of this is that he is talking about the Joker, but I believe that Bruce knows that Clark is Superman. This is now where we bring in Lex because he knows something about both our heroes. He is very calm when he interrupts Clark and Bruce's stare down. Lex acts as if he knows that Clark is Superman, and he does give that little punch at us "You should not pick a fight with this person." When he say "You should" he has a little bit of a pause and looks at Bruce, so he may even know about Bruce being Batman.
Bruce goes after Superman, and it probably sparks interest in Lex. He has these two "gladiators" fighting, and he most likely wants them both dead. This is why he created Doomsday (in the film) because he wants to be feared and have no one stop him. Since Doomsday has Kryptonian blood in him, Kryptonite will make him weak. We do know that Kryptonite will play a key role in this film because of the last trailer we've seen.
Now on to why Doomsday will work. It is no doubt that Doomsday has been spoiled, but we do need to remind ourselves that most people aren't comic book nerds. WB needs to give the common moviegoer a reason to go see the movie, and watching Lex Luthor create this monstrosity. Non comic book readers are going to be sitting on the edge of their seat thinking "OMG I need to find out what the hell that thing is!" Then we see Doomsday open his mouth, and we see Batman in peril. This could generate some buzz to get those non comic book readers to buy those tickets.
Doomsday is a much larger threat than Zod was because Doomsday is an animal. He doesn't have anything to fight for unlike Zod. I say this because I don't believe Doomsday is Zod rather than Doomsday was created with Zod's body parts. Doomsday is basically an animal, and he can only be stopped with Earth's heroes coming together. Just please don't have anymore moments where it gets cheesy. I love it when Superman and Batman look at each other and say "She with you?" Because you are bringing in Doomsday, doesn't mean you should kill Superman yet. The end of Man of Steel 2 should have a tease to Doomsday coming back to reclaim his revenge to Superman and the Justice League. Superman doesn't need a movie based on the Death of Superman, but it could give the DCEU some depth to it. Superman is going to be the leader, and the JL seeing their leader's death is going to affect them.
Batman vs Superman is going to have a trailer run before Star Wars: The Force Awakens, so maybe WB will be able to give people a trailer that doesn't spoil anything. Batman vs Superman deserves the hype, but we can't spoil anything. WB should rely on the comic book fans and the superhero movie fans to generate the hype like with what happened with Guardians of the Galaxy. If this movie fails, we shouldn't throw this universe away because there is a lot of potential. Suicide Squad is hopefully going to blow people away, Ben Affleck as Batman is as perfect as you can get, and it's nice because you have separation from the light-hearted MCU and you get a serious DCEU. Everything so far has been great for Batman vs Superman except this little slip, but it's working. People are talking about it whether they are hating on it or not, WB is getting more money in their pockets. We can all agree that we just want this film to be great, and it should be because it has everything we want in it. Batman and Superman beating each other like in TDKR, we finally get a Wonder Woman on the big screen, and we get a little sneak preview of what's to come with Justice League Part One.