Marvel has created the largest shared universe in the movie industry. They even crossed this universe into TV successfully. With DC's current TV success with Arrow and upcoming spin off Flash, will they try to tie their successful TV shared universe to their upcoming attempt at a movie shared universe?
Marvel's problem with TV crossovers is that much of the Marvel Universe is split 3 ways between Sony, Fox, and Marvel. Sony has Spider-man and all related characters/villains originating with it. Fox has the Fantastic Four and all associated characters/villains to them, plus the X-Men and all associated characters/villains to them, INCLUDING even the term/origin/everything dealing with "Mutant". Marvel retains rights to everything else.
Agents of Shield and the movies can't mention Mutants at all, and unfortunately Marvel leans way to hard on their mutant population in the comic books. Much of the MU revolves around The Fantastic Four and Spider-Man , as well. How do you write a universe spanning series when you can't mention 2/3 of it? Yet, even with these (many!) problems, Marvel pulled off the integrated TV/Movie shared universe because they established a centralized group to do it.
DC has no such problems. Since Warner Brothers retains all of the DC Universe's rights, the entire shebang is open to any writer/producer/director that comes along. This, in itself, could pose a potential problem to creating an integrated, shared universe; there is no centralized group keeping control of who does What, When and Where and Why to Who! How does that strike you?
The Green Arrow series has, thus far, been one of the best translations of a comic book to TV. Movie media to date. If the Flash didn't happen, something else would have had to; Arrow is that good. Extending franchises from it is an excellent way of creating an expanded universe, so they have They will likely keep going. Could this universe tie in to the current line of planned movies? Will it? Should it?!?
First, it can. Nothing mentioned in the movies or the series (yet!) precludes this from happening. Comic book stories are more than flexible enough to allow for cross overs, so why should other media based on these same stories be just as flexible?
Will it? I don't see why not. DC has had cross-over movies on the books for decades, but has never moved forward with them because of the complicated logistics of such projects. DC is only coming out with it's next line of integrated movies, including Justice League, because Marvel not only proved it could be done, but done successfully. Marvel also proved cross over with TV media is achievable as well. Will DC follow suit? They be stupid not to try!
Should it? What happens in the next movie will tell us that. Can DC follow in Marvel's footsteps and create their own successful Movie crossover? Only if they create their on centralized team to mesh the TV and Movie universes into one large, shared universe. We'll just have to wait and see.
Ngl, DC has the potential to create something awesome with this idea, but we all know they're going to try to follow Marvel's footsteps exactly.