A few points I'd like to make about BvS.
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I think the problem with having a character like Superman in a movie like this is everyone wonders why he didn't do this, why he didn't do that, etc. You can basically go on forever with stuff like this, why didn't superman save everybody, reverse time, etc.
First of all his powers are very limited in comparision to the godlike versions of him we've seen in the comics. He's not omnipotent and doesn't know everything that is happening. Also you have to realize they need to move things forward, theres only so much time and they can't explain every minute detail as to why superman was here and not there, etc.
This is a Superman movie and the entire DCEU is based on Superman, no superman no DCEU. He's the catalyst for everything: Zod, other meta humans, Doomsday, Luthor getting Kryptonian tech and knowledge, Darkseid, etc. In Suicide Squad trailer Waller says "ever since superman appeared all the other freaks are starting to come out of the woodwork".
His death and sacrifice led to the formation of the JL, his arrival has got the population of the whole DC universe asking questions about whether he's good or bad, this is paralled in real life as movie audiences and fans even ask themselves if this Superman is a badguy or just a guy trying to do the right thing.
I feel for Superman in the DCEU, the guys going through a ton of shit, people trying to kill him, people blame him for the world turning to shit, he's never really been happy. It's made him more relevant to me, I'm rooting for him now.
A lot of newer comic fans prefer Batman, Wolverine and Deadpool, and other edgier characters, Superman is considered out dated, obsolete, boring. People have turned their backs on him and forgotten about him, theres undertones of this in the movie as well. Supermans character has hidden undertones and messages which pertain to: war on terrorism, politics, religion and the state of the modern comic book fan.
Last point I'll make is I think Batman is being misunderstood a bit in this movie, there were a few scenes where I thought he was using deadly force but if you observe carefully he's actually not killing most of his enemies, it's very clever one scene where it looks like he's shooting at people with guns but it's not what it appears to be. Even the times he shoots or stabs badguys it looks like he strikes non vital areas most of the time. Have to watch it again to be sure.
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