The thing with the DCEU is that they're so determined to get in on the Marvel pie that they're trying to cut the line without understanding how Marvel got to where it is now. Man of Steel was trying to do two main things. It was trying to capitalize on the success of the kind of not great in hindsight Nolan Batman movies - even going so far as to plastering Nolan's name in advertisements - and it was trying to re-introduce the character of Superman to a new audience by divorcing him from the Donner/Reeves series.
This was the wrong thing to do since Superman as a character doesn't benefit at all from the grittier realistic aspect that can work with a Batman type. Superman is the antithesis to Batman and you need look no further than their costumes. One's black and intimidating and the other's colorful and inspiring. Man of Steel should've been to DC what the first Iron Man was to Marvel. When Iron Man came out, he wasn't exactly a top known character to the average person and Iron Man was coming in after a series of rather ho-hum superhero movies. It worked as a stand alone film and only hinted at a bigger picture at the very end. Iron Man could've been its own franchise. Marvel didn't have a plan. They clearly had PLANS. Plural. In case their Avengers gamble missed. Marvel had the luxury of a plan and time - time to introduce the main heroes while periodically adding more world building and inter-connectivity. Iron Man introduced Fury. The Incredible Hulk introduced Iron Man and thus the idea of synergy. Iron Man 2 brought Black Widow, and the main five leading up to Avengers there was the underlying constant of S.H.I.E.L.D.
Man of Steel feels largely irrelevant to its own universe to the point where Batman v Superman doesn't come off as a natural sequel and evolution of the character but a panic and an immediate response to the negativity surrounding Man of Steel. The only important bits of Man of Steel are the childhood scenes (to establish Superman's human morality, as fucked as it is in these movies) and the final battle with Zod because that's the big world revealing moment that Superman is force for good. Batman v Superman should not have happened as the second movie in this universe because Batman v Superman is barely a movie. It's two and a half hours of shoehorning and rushing edited to resemble a movie. People can talk about how BvS fundamentally misses the point of the titular characters til the cows drown but it's just a failure as a coherent movie.
It's not interested in letting their characters play on the screen. Everything has to be rushed because oh no Marvel's putting out a movie where like most of their characters are fighting and we gotta beat them to the punch. The reason Civil War worked - apart from having a vision and competent directing - is precisely because the audience has spent time with these characters since fucking 2008 and while I found that the relationship between Stark and Rogers was never all that 'friendly' on screen the conflict at least made sense given the narrative both of Civil War and the previous Marvel films. Batman v Superman doesn't have any clout because there's no real sensible or logical reason that these people are fighting and the audience has no stake in either one apart from "Well I like Batman so...go Batman?" or ditto with Superman. By the time the titular fight happens why should we care? The movie doesn't. It's just had a good hour and forty some odd minutes to try and convince you that this fight had to happen and instead it was too busy planning ahead. 'Here's a weird dream-vision with Parademons' 'Here's future Flash for reasons' 'Here's a break in the climax to give you trailers for our other heroes'. The main event of Batman v Superman feels like an afterthought.
It didn't have the confidence to let the conflict be the conflict. It didn't need Doomsday and it made the already bad Death of Superman story fall limp. The climax of the movie wasn't a climax, it was just moving pieces for the next one. The only reason Superman died is to facilitate the third act reveal in Justice League because they're not fucking doing the Four Supermen angle unless they're really clueless. You haven't gotten invested with these characters by the end of BvS to make the ending play. That's the basics of the basics: Make your audience CARE. DC was thinking they could get by on name recognition alone whereas Marvel (and I do hate to play the comparison game but it works) had to make people care. Who the fuck cared about Thor? Ant-Man? Captain America? While Marvel hasn't had a perfect track record, they at least know how to put together a stand alone film while still having it be part of something larger. DC doesn't, at least not yet, because it's bashing you in the head with a crowbar and forcing you to care not about what you're watching but what you COULD be watching in the future.
In Winter Soldier when that one dude is talking about other supers he just casually drops 'Steven Strange' as a subtle nod that fans would pick up on and the casual 'only watches the movies' sorts will now understand.
Batman and Wonder Woman should've had their solo efforts first. Wonder Woman, based on the trailer, has no bearings on Justice League and is an origin story and based on the rumors about the Ben Affleck helmed Batman movie it's a similar scenario there. After those movies came out, introducing Wonder Woman to audiences and re-introducing Batman then you have a reason to care and things wouldn't feel so utterly forced. DC has no confidence in itself or its characters and no real game plan other than "Justice League ASAP".
Suicide Squad is an anomaly because it feels even more disconnected. Suicide Squad is like the DCEU version of Guardians of the Galaxy. Guardians at least fit in by showing more of the Infinity Stones and Thanos and the overall cosmic element; Squad, with the exception of the Batman cameo, doesn't feel like a part of the same universe and it's thanks in no small part to how they introduced magic. Poorly, of course, but in a universe that was careful to make things seem at least more realistic now there's magic happening. But Squad has the same problem of Batman v Superman in that it's an incoherent mess that fails to make you care about these characters. This was their carte blanche. They were introducing some pretty D-Tier characters and re-introducing a character people liked because of Dark Knight and they fucked it up completely.
There's nothing interesting in Suicide Squad, a movie that feels more interested in making sure you buy the soundtrack than giving a shit. It's like watching a hackjob for two hours. There are no stakes in the poorly shot action scenes. "We can't shoot these weird mud zombies" Proceed to do nothing but shoot them and win. And the big final fight scene makes absolutely no sense other than "Well we have to make our villain dumb and less threatening because otherwise we've written ourselves into a corner." Enchantress is literally a powerful ancient magic thing and she decides "No I'll fight these people in hand to hand I guess". It's terrible writing in a movie that is nothing but terrible writing.
Why does Suicide Squad exist in this canon? What did it do to belong? Why was it not its own thing? It exists as a movie just to have the mid-credits scene with Waller and Bruce Wayne but that same scene gave no new information because it was just re-stating what was established in the last movie. That's not how you tease.
DC needs to let its directors have more creative control. Marvel may run a tight ship but it seems at least that it lets its directors work well within the guidelines. DC is so reactionary to criticism that it further hints at them having no real plan in mind. DCEU is the movie version of someone doing a school project in the period before it's due.
Wonder Woman has a chance, a small fucking chance, but a CHANCE to be good simply because it's removed from the present day DCEU. But I'm not holding my breath on that and neither should you.
The first step to salvaging the DCEU without just sinking the ship and starting over again is getting rid of David S. Goyer. They did that and brought in Chris Terrio which, hey dude won an Oscar for screenplay. If they're determined to have one director helm the main movies then the second step is getting rid of Zach Snyder because he thinks shooting a comic book movie is just 'copying the panel' like he's tracing and he's also a shit director that thinks visual bullshit is more important than anything else. The third is getting a Kevin Feige type because it doesn't seem like Geoff Johns cares at all. And the fourth is having some fucking confidence in your product. Suicide Squad and parts of Batman v Superman are so frustrating because behind the shit are elements clearly chopped and skewered from better, more realized movies.
DCEU isn't totally fucked but they're flailing about and they need something to throw them a fucking lifeline.