The following piece includes major SPOILERS for Justice League.
Seemingly as part of achieving that goal, Justice League spends as little time as it's able to get away with setting up future movies or paying off loose threads from its team-up predecessor (save, of course, for one very, very big one) which leads to a much more "streamlined" moviegoing experience more focused on action scenes, jokey dialogue exchanges and "hero moments;" but also one that inevitably leaves a lot of questions unanswered - both in terms of story-threads it raises and leftover details from Batman v Superman that apparently are no longer priorities. Here are the ten biggest things yet to be answered now that the League's debut is in the history books.
WHAT WAS FUTURE FLASH "TOO SOON" FOR?
One of the most talked-about scenes in Batman V Superman involves Bruce Wayne waking up from one bad dream ("The Knightmare") seemingly into another: Ezra Miller's Flash - whom he hadn't met yet at this point - pops up of a mysterious energy field wearing a futuristic armored version of his Flash costume and sporting an older, goatee-and-mustache look overall. Apparently, he's come with a warning, shouting out important-sounding declarations about how "You [Bruce] were right about him!" and that Lois Lane is "the key!" Midway through, though, Flash seems to determine that he miscalculated his appearance, asking "Am I too soon!?" before vanishing completely.
It's a comic-book reference of course, specifically to Crisis on Infinite Earth's famously featuring an encounter between Batman and a spectral incarnation of Barry "The Flash" Allen early on that turns out to be a dire warning flung backwards through time from later in the apocalyptic story. But it also seems to be a setup for later events, either for the ending of that film (where Lois plays a significant role) or a future one.
It now seems like it could have been an allusion to the plot of Justice League, where Lois turns out to be the "big gun" that can talk Superman down from a brief bout of post-resurrection super-anger. But either case is unknowable, since nothing about the scene (including Barry's facial hair, alternate costume, ability to travel backwards through time or whether Bruce Wayne recognizes him) has been addressed yet. Rumors persist that Flashpoint - the renamed solo Flash movie - will be a time-shuffling story used to "soft-reboot" the entire franchise, but that wasn't the plan when the "Am I too soon?" scene was shot, so it's still anyone's guess.
WHAT DID WONDER WOMAN DO FOR A CENTURY?
According to the ending (and incidental story details) of Batman V Superman, Wonder Woman "walked away from Man's World" for a century following her service in World War I. What she's been doing for all that time isn't exactly clear, save that she apparently didn't return (at least not permanently) to Themyscira with the other Amazons. So what was the most powerful superhero on Earth (until Kal-El arrived) getting up to between winning WWI and slipping her tiara back on to help battle Doomsday? Supposedly, Wonder Woman 2 will find Diana getting involved in the Cold War during the 80s, but that still leaves a long stretch of time unaccounted for and a lot of major world events (including a whole other World War!) that it currently seems like she sort of "sat out."
Presumably her own sequel(s) will correct the record, but a popular fan theory is that Wonder Woman was at one point supposed to have a much darker ending - i.e. Diana actively removing herself from the affairs of humans after learning that her nemesis Ares didn't actually have to "make them" fight wars and be awful to each other - that was rendered more optimistic (but less congruent with her "pre-set" future) after the backlash against Batman V Superman.
WILL ANY OF THE DARKSEID TEASES PAY OFF?
Even before Batman V Superman started teasing at it, it was widely assumed that alien dictator Darkseid and his minions - originally the antagonists from Jack Kirby's ambitious New Gods series in the 70s - would be the main villains of Justice League. And while it's still believed that this was at one point meant to be the case, that changed sometime around when Warner Bros decided that League would be only one movie rather than a planned two-film back-to-back shoot; instead, the heroes wound up facing the Lord of Apokolips' henchman Steppenwolf. But while Darkseid get's name-checked at least once in the film and was heavily teased by Batman V Superman (Batman's vision of a nightmare future included a giant Omega symbol carved into the Earth itself), there's no explicit confirmation he's coming.
In fact, apart from Steppenwolf himself, the Parademon foot-soldiers and the Motherboxes, the film seems to be actively avoiding even the suggestion that the broader New Gods/Fourth World cosmology exists in the films at all, and those not already in the know would be forgiven for assuming that Steppenwolf's defeat is the end of that entire threat. Instead, the film's expected post-credit scene is devoted to teasing a cinematic version of the Injustice Gang/Legion of Doom concept. Is it possible that the myriad of changes of plans to the DCEU plan post-Batman V Superman (rumored to include a new actor to play Batman and a possible soft-reboot in Flashpoint) might have included dropping plans to involve the New Gods characters altogether?
WHAT WAS BATMAN'S "KNIGHTMARE" ABOUT?
"The Knightmare" remains one of the Batman V Superman's iconic sequences, even among those who didn't care for it (or the rest of the film): a bizarre stretch of film in which Batman either imagines or predicts a Mad Max-like post-apocalyptic future hellscape, blighted by Apokoliptan engine towers and Darkseid's omega symbol, where he leads a failing armed resistance against a dictatorial Superman and his army of armed soldiers and Parademons. It certainly looked cool but didn't have much to do with the actual story of the film (i.e. Batman already wanted to kill Superman for reasons having nothing to do with any of the things being pictured here) - leading many to assume that it was meant to be a preview of things to come in Justice League regarding Darkseid and the New Gods.
But while Apolopitan advancer Steppenwolf indeed turned up as the heavy of Justice League, any of the broader mythos that might've been implied never sees the light of day. Also, rather than becoming a villain, Henry Cavill's post-resurrection Superman is mostly just angry and (apparently) allergic to shirts until a quick trip to Smallville with Lois Lane puts him back on the right path. So where did the "Knightmare" come from, then? We may never know.