The question was asked for years prior to any announcement of a "Batman v Superman" film or plans for a Justice League franchise: How are they going to introduce the characters of the Justice League all at the same time?
What people don't seem to understand is that these characters have been introduced together -- successfully -- several times already in DC's animated universe.
"But, Andy, those are cartoons!" you say.
Whoa, there. This is not "Super Friends." The modern DC animated originals are dark, gritty, and they're as true to the characters as you'll ever see.
Strangely enough, and arguably most important, they're written -- or at least plotted -- better than the major studios can seem to pull off with their massive staff and budget.
So if you still have a sour taste in your mouth after seeing "Batman vs. Superman," retreat to your Fortress Of Solitude and check out these badass DC animated offerings to begin the healing process.
In summation, I don't think it's even remotely unreasonable for the major studios making these live-action DC films to look to the DC animated universe for inspiration and storytelling guidance.
At this point, it seems pretty necessary.