You know I think WB should have just bit the bullet back in February and sacked Snyder then. The whole critic embargoes, trailer showing best parts of the movie, worldwide release. They knew it wasn't going to get the best reception. The only thing BVS had going for it was the hype, and marketing. Nearly all insiders where unanimously saying the movies was good. The movie was pretty well hidden.
A Snyder departure back in February would have set alarm bells off to everyone that the movie wasn't good even if the headline read something like "Zack Snyder wants to spend more time with family". And WB had no confidence in Snyder or BVS. Two months before production wouldn't net you someone like JJ Abrams or Cuaron. But they could have aimed for a lesser known up and comer like (tossing in Joe Cornish Attack the Block as an example or Alex Garland Ex Machina). Took Marvel little over two weeks to find Peyton Reed after Edgar Wright left.
WB put themselves into a no win situation, and frankly I have zero sympathy for them. They were so hell bent on achieving Avengers level success without putting in the hard work to do it. We are essentially back to where we were 20 years ago with Batman and Robin, only this time WB are pressing ahead regardless, which is frankly foolish. But WB have no-one to blame but themselves.