I feel like I've created this thread once before,
I remembering discussing Iron Man vs Batman at one point.
Currently, plans call for the DCU to ultimately combat the MCU with JLA Parts 1 and 2 and while I'm moderately excited I don't think this is the way to go. Marvel is banking on what's essentially a two-part film adaptation of the Infinity Gauntlet to cement their comic book film dominance and it works because the Infinity Gauntlet, for better and worse, changed the Marvel universe. What could DC do to combat this?
I think you are jumping the gun here. So far DC is in the stage where Marvel was after Iron Man came out. They have built on to that for seven years now. Marvel has had two phases before truly building up to Thanos. The new Batman isn't directly tied to the Nolan films (supposedly), so we are just at the very beginning of Phase 1 for DC. I honestly believe that the DC is making, and you and other fans are pushing for it, is rushing to bring it all together. Instead of letting each character kind of build their own mythos first they are bringing at least three of them in on their second film.
Again, in theory, it's extremely simple: Crisis. On. Infinite Earths. I cannot express how badass it would be, perhaps more so than seeing Thanos wreck any and everyone with absolute ease, to see Anti-Monitor absorbing and abolishing entire universes. It would absolutely involve having to reboot old characters, introduce a slew of new characters, and create a rich movie-friendly lore that works within the story. It can be done and the proof of that is Marvel doing it with the eventual payoff in Infinity War. and they're both of arguable scale.
If DC can pull this off this quickly it is purely because Marvel setup the audience for the whatever gets thrown their way. That said, their TV shows are kind of setting a precedent, even if they aren't direct tie-ins. We can see the DCU in its glory in Flash and Arrow.
But that creates a new issue. Not bringing the TV versions into the films means that Crisis is already being done on TV. "Flash Disappears in Crisis."
And that is where I think DC has already stumbled. Why reinvent Flash and Arrow? They exist. They make small references to the JLA and other characters, as well as some universe spanning storylines. Fans of the show will see them in the movies and question every tiny difference. Why change it? It worked as it was. In fact, it will get bigger with a Legends of Tomorrow series spinning off from Arrow and The Flash.
Add in to the CW DC universe that there will be a Supergirl show on CBS and Titans on TNT. Supergirl will include Superman, but not the movie Superman. Titans will have Robin, who was trained and worked with Batman, but not the movie Batman. Just to make it even more confusing, Supergirl is not in the same universe as Titans and not in the same universe as the CW trilogy.
I'm leaving out Gotham because it takes place as an origin story to whatever version of Batman you want it to be and nothing in the show will ultimately affect any other show or movie.
Some Marvel characters are separated by studio deals from MCU, but only Quicksilver has the risk of cross-brand confusion so far, and the two versions take place so far apart in time and space that they seem like completely different people. And it is possible to do TV shows that are part of the canon but not a part of the story. Marvel is doing it with The Defenders. Daredevil vaguely references the attack on New York, but no one is expecting to see Iron Man go flying overhead.
DC will need to be redundant or find new stories on the scale of Crisis. The Flash created a whole new problem with DC. It is arguably one of, if not the greatest comic book TV show ever. It has taken on concepts that you would expect to only find in films. And Arrow is a part of that, not to mention the moment a Lazarus Pit came into play we were in movie-quality territory. Now, a couple of writers are working on a Flash film. Their biggest competition? The Flash. What can be done in 2-2.5 hours that will make us accept it as equals to a 22 hour story? Likely twice that much by the time the movie comes out. Who in Flash's Rogue's gallery will be big enough to be just a single big screen challenge on par with Reverse Flash, Captain Cold, Heat Wave, Firestorm, The Trickster, Boomerang, Grodd, etc.?
DC's biggest challenge is their own success. With the TV shows doing extremely well and the one movie they have so far leaving a bad taste in some fans' mouths as well as a new casting decision that has caused some controversy, the films have an uphill battle to meet the quality the TV shows have fans expecting.
Maybe if the movies struggle they will fall back on TV. Even The New Adventures of Lois and Clark had a favorable fan following.
I would love to see a culmination of JLA members in their own TV shows with a group JLA miniseries over the summer every year.
People will see any movie with Batman/Superman in it, DC's main job is making Heros like the Flash, Green Lantern, etc appeal to the casual movie goer in the same level as Cap or Thor for example.
Flash, Green Arrow, and the Atom already do, along with side heroes like Arsenal, Red Arrow, Firestorm, and Black Canary. Their TV versions have opened their worlds up to the general audiences.
Either way they'll get all the money from their movies even if they are average.
I am/was a lifelong, die hard Superman fan. There are video and pictures of five-year-old me at my birthday party in a Superman tank top with a Superman hat having a Superman birthday party. I looked up to Superman so much that when he became Evil Superman in Superman III I cried. After MoS I am not sure I am willing to pay theater money to see BvS.