No point wasting millions on marketing a movie they already know is going to bomb. Hence no Superbowl teaser despite Stranger Things Season 2 having one.
I'm a bit hesitant to say that Wonder Woman will be as bad as Man of Steel or Batman v Superman. Given that it has a different director, writer, producer, and editor.
It's the first film in the DCEU where neither Snyder nor Goyer has any real involvement, so I'm gonna wait and see.