First thing: Chris Nolan is mya favourite director
Second thing: I like Snyder's movie, but i don't think he is the right person to direct a movie like this.
Snyder, talking abou watchmen and 300 ( I lie it), admitted that he had copied the shots from the original comics. Probably the movie has a bad review just because it has disappointed the high hype.
Snyder wasn't Warner's first choice but the major needed a guy who could direct the movie in tight times, a guy who didn't care too much abou the story (instead of others directors such as Aronofsky o Duncan Jones)