I've read some of those negative reviews and I really think that there's a whole lot of negative confirmation bias going on here because this is by no means a bad film.
It's perfectly fine if people don't like this film, there's no accounting for taste, however the things they are writing to support their view are absolute bullshit from a purely objective standpoint, so I'll just try to dispel a few most common complaints here.
SPOILER WARNING!
I'll avoid plot spoilers beyond what you've already seen in the trailers, but there will be a description of the plot and character arcs in general terms, so if you really want to go in fresh don't read beyond this point.
So...
"no character growth"
All three characters have arcs that they complete.
Batman starts form an angry, pessimistic, resigned individual and ends up as a hopeful, optimistic, newly determined guy.
Superman's arc in Man of Steel was him finding his place in the world, it continues here to him dealing with the world's reaction to him.
Wonder Woman starts withdrawn from the world and ends up rejoining it.
"incoherent plot"
The plot of the movie is fairly straightforward, Lex sees Superman as a threat to humanity and seeks to destroy him by manipulating events so that both the world and Batman develop a negative and doubting view of Superman.
This one I can somewhat understand because there is a lot of stuff to set up the Justice League movies going on on the side, and I can see how people who are unfamiliar with DC lore might see it as "tacked on", but I found it to be very organically integrated.
"lacks subtlety"
This is the one I have to most vehemently disagree with.
And this I think is where Marvel films are the most to blame because they have conditioned people to expect the superhero films to be entirely straightforward and literal. Even the really good Marvel films like Winter Soldier are completely on the nose about what they're doing. While there are some very unsubtle things that people have focused on, there is a whole lot of subtle stuff going on here that I see people overlook or not give enough credit to.
"depressing tone"
People seem to confuse serious with depressing.
I think Terrio's comparison to Empire Strikes Back was apt. Yes, bad stuff happens, but at the end characters are not "depressed" they're hopeful and determined.
"no fun"/"humorless"
The movie is serious, but it's not humorless.
There are no laugh out loud clown moments in this film, but there is humor. Alfred being snarky to Bruce all the time probably being the most obvious example, though others have humorous lines throughout the film which are subtle and don't jump out. The fact that people find it humorless if it doesn't have a giant "laugh now this is joke!" sign says more about them than the movie...
"CGI orgy"
What you see in the trailers is seriously pretty much it.
The Doomsday fight does not have that much destruction, the landscape you see in the trailers where they fight is a preexisting condition as it takes place in a condemned, abandoned section of the city, there's no new citywide destruction scenes.
That whole fight has less CGI and feels shorter than the Hulk v Iron Man fight in Age of Ultron and the fact that people have taken an exception to this one kinda speaks to the negative bias that greeted this film out of the gate.
Anyways, I'd urge people to go into it with an open mind.
The cinematography and music are worth it even if you end up disliking everything else...
