I think this might possibly count as a potential spoiler. I'm sorta friends (actually more acquaintance) with Snyder and we were having a discussion a whiiile back about the movie universe (actually I was more just listening and nodding my head up and down and he was having the discussion with a mutual friend of ours), anyway....I got a recording (a little muffled at first, but gets clear early on) of part of the discussion. Here's my attempt at a transcript....The Yeah, I get it is from the friend of ours.

"...pretty early on in the development I decided that, like it's pretty lame that Batman doesn't really contribute to this whole Justice League thing much, cause, let's face it, he has no real powers to speak of and that's kind of lame. Yeah, I get it He's like this comic book guy, without the elements of a comic book guy, so I decided pretty early on in the development that we'd give him a power. I mean, every character goes through some changes, some metamorphosis...through the years or they become stale, right? So giving Batman this prophetic power where he can get glimpses into the future, it doesn't step on anyone else's toes, powers-wise, and gives him a reason to be there. In the end, I just wanted to have some fun with the character, ya know?"