If you're alluding to what I'm thinking of @Scar&Hyenas, he didn't say it was specifically what he'd do to the Nolan movies, it was his reaction to people saying they were "dark," and something he might do instead in a Batman movie to make it "dark".
And yeah, what he said was tasteless, no doubt, but I basically agree with the claim that the Nolan movies aren't all that "dark". And when he did his own "dark" Batman movie, nothing like what he suggested ever came up, and he managed to make it dark without that.
On the topic of Snyder re-doing someone else's movie to "fix" it, I don't think he'd really want to touch that one, given his reaction when someone tried to "fix" one of his movies. I think he cares too much for an artist's vision to mess with someone else's.