I haven't seen The Shape of Water, mainly because I'm not a fan of Del Toro's style of story telling. I respect him, and his work, but it's not for me. But I think the core difference is that Del Toro's film isn't supposed to be horror while Get Out is.
Dunkirk was truly brilliant, but I didn't expect it to win because it wasn't auteur enough. It was a brutal film that wore you down, those films don't usually do well at the Oscars.