For some reason people seem to care what Kevin Conroy thinks about Zack Snyder's take on Batman, so let's take a look at what he has to say. Conroy has been the most famous voice actor to portray the Dark Knight in a variety of DC animated movies and TV series, which gives him better insight into the character, I suppose? Not sure I agree with that, but let's roll with it. Speaking with IGN, Conroy really feels like the portrayal provided by Zack Snyder in Batman v Superman: Dawn of Justice was way too violent since he has no problem killing folks. Pretty sure he decked Harley Quinn in Suicide Squad, too....
“Personally I love the fact that Batman — in the stories I’ve done, and the way he’s been rendered by Bruce Timm and Paul Dini, the people I’ve worked with most closely — he never kills anybody. He doesn’t cross that line. Batman is not a killer. He puts them into Arkham Asylum, which is what is so brilliant about the Arkham Games – someone realized, ‘My god, all these incredible villains are all in the same institution — let’s get a video game in there.’ It’s a brilliant idea. But the fact that Batman never kills anyone — I loved that fact...In the most recent live action movie, that seems to have been a line that was crossed and it’s not one I’m particularly comfortable with."
I know Batman has a code against killing in the comics, but he HAS killed before. I think when Snyder has referenced The Dark Knight Returns as evidence he's mistaken, but there are other times. If he chooses to use those instances as justification for his violent take on Batman then so be it. He's not without support in his characterization, that's all I'm saying.
If Conroy is so worried about mischaracterizations of Batman, he might want to look at Batman: The Killing Joke, in which Bats bangs Batgirl then promptly disses her until she gets shot by the Joker. I wonder who voiced Batman in that....oh wait, it was Kevin Conroy.