To be fair, we kind of all saw this coming as the movie was being made and stuff was being leaked. My first clue that Warner Brothers was going to not be successful like their competition (Marvel Studios and Disney) was their shared universe plan. Instead of doing a few solo films which culminate in one big super team-up (like the Avengers) they were going to do the team up first and then split up into solo films.
The reviews hate on basically two fronts. The first being the pace and plot of the film, which on the surface doesn't seem to make sense. The second is how uncharacteristic the characters are.
I agree with the first point. There are basically two stories being told in this movie, the Batman story, and the Superman story. Two main plotlines are being told at the same time from two different perspectives. These perspectives then collide in the first part of the third act. The reason the plot makes no sense is because it's two stories being told at the same time, and neither has enough time to establish itself. So instead of one good well rounded plot, we have two semi-realized stories competing with each other. Both of which create their own plot holes. On top of that, there are other side plots and half plots thrown in to add to the confusion.
So, there are problems with the film and it's writing, and plot. However, how the characters are portrayed is not one of them. Comic book fans are the loudest, most difficult to please critics in the history of media. This film once again proves it. The main complaint seems to be "Superman is not Superman enough".
The Man of Steel has had a publication history of 78 years. Since his inception in 1938, Superman gained the powers of flight, xray vision, and heat vision and became bullet proof in addition to his super strength and super speed. He was joined by other super family members like Supergirl, Superwoman, Powergirl, a super dog and a super horse, a few clones, and an entire miniature Kryptonian city in a bottle. He married Lois Lane. Superman died in 1992, came back to life in 1993, and lost his powers altogether for a time in 2006. Superman evolved from an aggressive vigilante who killed, committed arson, and fought the police and national guard to a reserved, responsible protector of justice who upholds the law and works with the authorities.
My point to all this is Superman, like anyone who has been around for almost 80 years, has not been the same and deserves to be written as a more complex, multidimensional character. The fact that Superman has so many superpowers, and is essentially unflawed and indestructible has set him up to be an uninteresting and unrelatable failure. Writing interesting Superman stories is difficult. There are really only two stories to tell. The first is Superman meets another overly super powered man/thing and they punch each other silly until Superman comes out on top. The second is Superman has an existential crisis about how he's the last of his kind, or wrestles with his absolute power and responsibility.
Fans of comics want to see the comic up on a big screen. But which story? There are 78 years of Batman and Superman stories, and not all of them are good. The Superman in Man of Steel and Dawn of Justice is certainly the same Superman from the comics, it may take some looking, but you'll find bits and pieces of him popping up in storylines all throughout his publication history. Personally I would rather have the Henry Cavill Superman badass than the Christopher Reeve no personality Superman, or the Superman straight outa Dragnet that was on television in the 50s.
Instead of complaining about Superman, fans ought to be excited about the awesome Wonder Woman performance. Saying she stole the show and saved the film would be an understatement. I'm kind of disappointed we have to wait until 2017 for her solo film.
The more I think about this film, the less I believe it to be a bad movie. Could the writing have been better? Probably. Could the reason Batman and Superman stop fighting and team up been more realistic? Yes. Are there parts of the film that seemed unnecessary? I can think of a couple dream sequences that could have been left out. But otherwise, the film holds up, and delivers what the obvious title promises.