I would guess if Wonder Woman had come out before Captain America it would have been set in World War II. That said, it would have looked very different in a bunch of other ways, if it had happened at all. She has a lot of the same heroic guardian qualities, and a bit of the fish-out-of-water element, though not as much as Thor. It’s also a better superhero film than DC have managed this decade.
I may also be overreading the Buffy influence in the moment with the sword. Or maybe not.