In Batman v Superman: Dawn of Justice* Batman has been operating in Gotham for 17 years. That means there are a lot of untold Batman stories in this universe, which is different from the one established by Christopher Nolan in his Dark Knight trilogy**. And that means some of these stories could be explored in future films, if Warner Bros is going to maintain this continuity for the next decade, as they seem committed to doing.
One story that could yet be told is the death of a major player in Batman's supporting character gallery. Read no further if you fear spoilers, however minor (and this is minor).
You sure you want to find out who is dead when Batman v Superman opens?
Okay, for the curious: in this continuity James Gordon has, at some point in the past, bitten the dust. How and at whose hands I cannot tell you - all that's noted in the script is that there's a memorial plaque to James Gordon. This explains why the role wasn't cast for the film, at least.
What does a dead Jim Gordon mean for BvS? Not much technically - most of the story takes place in Metropolis although there are two major fight scenes in Gotham (one where Superman comes looking for Batman and a climactic fight scene) - but it could have big consequences for the new DC Movieverse. While pre-Terrio drafts of the script mentioned a deceased Robin, later iterations closer to the start of shooting don't - perhaps in this continuity The Joker killed Jim Gordon instead of Robin? That would be an interesting spin, and something that could feed into future Batman movies.
It's worth noting that we simply don't know what Warner Bros' plans are for future Batman movies. They surely have Ben Affleck nailed down for a few films, but will they keep him in the Justice League franchise and then make Batfilms that take place over the course of the character's 17 year career with a younger lead? Or will they make Batfilms that take place in the here and now, with an older Batman and a dead Gordon?
I don't think we're going to be too worried about a lack of solo Batfilms, as Batman is the lead of Justice League - he's the guy who puts the team together - and I'm sure we'll have lots of Batfleck screentime between now and 2019, when Justice League 2 hits. But it's still intriguing to consider how WB will be treating their DC Movieverse playground, especially as they're beginning it so very in media res.
* the actual title.
** although this version of Alfred is very similar to Nolan's, down to his insistence on giving Bruce Wayne advice in the form of lengthy stories. In this movie he advises Bruce on his conflict with Superman by telling him a long tale about two competing samurai who come to blows while trying to save a village.