In order to have a cinematic DC universe, the only option has always been to jumpstart it all at once. Man of Steel was nothing more than a toe test for the water. If they were to bring in the universe proper, it would have to be all at once or none at all.
That's because that's how the DC universe is set up. An absurd amount of characters, both villains and heroes, with literally world-shaking events at a near constant rate. If you are going to open it up at all, nearly every story that spans more than a single geographic area is going to affect the entire world, if not the entire dimension, so if these other characters are already existing, but in the background, then they will show up in any consistent universe.
Any reasonable attempt so far to portray the DC universe on film has been so limiting as to be almost unrecognizable. As mentioned earlier, DC has world-shaking events at a near constant rate. I recently watched the first season of Young Justice and in one episode they were stopping an already erupting supervolcano (one of the regularly cited "end of humanity" events) and in another they prevented a black hole from forming (that had already started to suck in mass and rotate). This is a show about a team of superheroes that go in under the radar. In another episode, all major cities in the world were under attack by gas-spewing, regenerating supermassive plants.
I can see DC fans cheering for the terraforming mech in Man of Steel because that's the type of event that happens regularly in DC proper. I was left underwhelmed. It seemed like nothing but bloat, and an absurd escalation to an already world-changing event (alien super-powered army invasion wasn't enough). And that's ignoring the illogical choice to terraform Earth to be more like Krypton anyway (Kryptonians are super-powerful on Earth, why would they want to do anything to make things more like Krypton?).
The destruction of Metropolis in Man of Steel maybe isn't expected, but it's par for the course in a normal DC storyline.
The DC universe is so bloated, so incredible, that it lacks credibility on the screen. If it's represented in cinematic form the way it's presented in comics and many animation, then you're left watching an, "oh, that's cool looking" movie and that's it.
One of the reasons why Young Justice season 1 is involving and interesting is that the characters all go through some pretty interesting arcs, have emotional depth, have complex relationships, and feel like real people. It also helps that they aren't so absurdly overpowered as to require Darkseid or Doomsday to pose a challenge.
In general, you can boil down the characters in the DC universe to three-dimensional characters. There's so much backlog for them all that any halfway decent writer can do that. But they can't do that with the spectacle that is the DC universe proper.
How can you care about the struggle a character has to go through emotionally when literally in the next scene they are flying through the center of the planet or running faster than the speed of light?
I've always heard that DC has better stories and Marvel has better characters. I don't think that's true on either side. I think DC has more spectacle and Marvel has more character development.
They're both soap operas at the end of the day, but when translating those soaps to the big screen, character struggle with high stakes is 1000% more engrossing than big, bloated set pieces that aren't properly built up.
I get pretty tired hearing pundits implying that in order to do a DC cinematic universe it has to be done all at once. Their reasons are never stated as being in-universe reasons, but rather so WB can start to compete with Disney/Marvel on a financial stage. What? Are movies a zero-sum game? Can only one superhero movie studio do well per year? This is absurd, and it's the kind of thinking that sunk Spider-Man 3, Amazing Spider-Man 2, and Fantastic Four.
It's hard not to compare the different franchises, but let's discuss some things. First, when one of the main characters in the Marvel Studios Cinematic Universe (MCU) feels something or has a backstory or anything like that, guess what, we've all seen those things and can feel those things. They've been set-up. Arguably one of the best parts of the last trailer is Cap saying, "I could do this all day," because it's such a call-back to the first Cap film. This is 5 years of set-up for that one line. It was perfect.
In the newly rebooted X-Men franchise, the struggle between Magneto and Xavier and how Mystique is affected has never been clearer or better shown. In the first version of these movies, we relied on communal understanding of the characters and they still showed the struggle, but we didn't feel it as viscerally as we feel it now between these three. There's internal logic to the decisions the characters make.
For Deadpool, it's absurd and it's designed to be absurd, but we got an origin story anyway. It reset the origin from X-Men Origins for the character and now we all have a new understanding of the character. Deadpool is arguably one of the characters that could get away without explaining anything because more than an action superhero movie, it's a comedy. It has the other parts too, but the goal of the entire thing is sheer fun.
Maybe I take the storyline and characters too seriously for non-absurdist stories that are supposed to be good stories. I can't turn off my brain when I watch these characters because I care too much about them. I want the stories to be good. There's a reason I don't go watch Transformers anymore.
And then there's the current DCU.
It's hard not to feel like the entire motivation is out-of-universe. Let's rely entirely on the communal understanding of the characters and not have the motivation come from within. I can rationalize the end of the Man of Steel movie and much of Superman's actions throughout it, but I'm rationalizing it, and I'm more experienced than the average person going to a Superman movie. People don't know the stories from the comics as well as they do anything on TV or the big-screen. We have an idea of what Superman is already, and it's not what they gave us in Man of Steel. That's fine, but you can't set up the movie relying on the audience already knowing the characters if you're going to give us a different character without explanation.
The focus feels like it's on the spectacle and not the characters. And I think that's going to be the problem with any DC universe proper set-up that doesn't have a tight, controlled focus.