I know this is a dorky observation...but I think the idea to make Wonder Woman a WW1 movie and not a WW2 movie might make it work.
I think people are sick of seeing Nazis as the go to bad guys in fiction. I think it's rare to see WW1 as the setting in a movie. And to me the Germans weren't the clear bad guys they were in WW2...WW1 involved messy alliances and the countries involved were more morally gray IMO.
But I didn't really see much grey... aside from the colours of everything.
That said, it worked anyway.