The thing is, for all it's troubles Man of Steel was a promising start, imo, to what could have been a good Superman movie slate. But at some point Snyder was put on the position to spearhead the DCEU, he asked for Batman and got it, we know how it went after that.
I like to say that Man of Steel biggest flaw is BvS. Maybe if Snyder had less power, and had only Superman to work with, the character wouldn't get sideline like he was. WB should never have given so much power to a single director, when they realised where he was going with their universe it was too late.