If you read my Marvel article of the same title then please just take the introduction there and flip it on its head. For all I really like a lot of what's been put out under the banner of the DCEU, critically and commercially it just hasn't really worked out for them. Suicide Squad made them millions at the box office but got panned by critics, Justice League was all about sparking a huge extended universe and didn't even get to make its own sequel, Batman Vs Superman should have set the world on fire but... well... Martha.
There's been plenty that has worked though. Gal Gadot's Wonder Woman has been a revelation, and Aquaman was the perfect B-Level origin story, but to date, most of the big hitters have either been canceled or recast entirely. In 2016 we were speculating how Jared Leto vs Ben Affleck would play out across Gotham City, but, by 2019 neither are still in the role.
So, let's pretend DC has a time machine and can nip back across their own back catalogue righting the introductory wrongs that have got them in the mess they find themselves in today. Who comes in earlier, who comes in later, and who doesn't even come in at all?