Change EVERYTHING. Instead of Greek mythology and "magical white lady in a swimsuit saving the world", change the origin radically while still preserving the core identity of the character. Less of the cheesy spandex style, and more of the Christopher Nolan-style "realistic" super hero films.
- Skip the Greek stuff, and instead set the origin in South American mythology, Incan, Mayan, or something even more ancient (and possibly completely made up). This avoids comparisons to Thor, and gives a fresh, unknown feel to the character.
- Make Wonder Woman a character based more on being a capable fighter than a pretty lady, although she can certainly be played by someone attractive. Brief thoughts on casting? Odette Annable, Marilyn Cortez, or someone young and fresh like that. Maybe even a very young (18-25) and unknown Latino actress?
- Instead of having her created from clay on a secret island someplace, have her be a normal girl living in a major American city. She's a distant descendant of the original ancient "goddess", suddenly and for some reason imbued with that same power. This allows you to have a real, human character with her own life and friends, suddenly able to fight like the paragon of an ancient civilization. She speaks English, she speaks Spanish, she's smart and strong, but she has a tough life that only gets tougher when all this hits her.
- There should be some real question about whether this is legitimately a supernatural thing, or whether the protagonist is delusional after being under huge stresses in her real life, and has just "snapped" and started believing she's "Wonder Woman". This question in the audience's mind should be cleared up at the climax, when it's made clear that yep, she's not crazy. Maybe it's after being defeated and locked in a cell by the bad guys, only for her to fight through her mental doubts and finally embrace the full power of the Wonder Woman. That way you can have her be just really really good for most of the film, and only give her above-human strength, speed, and fighting ability right at the end.
- Speaking of super-powers, don't make her as strong as the Hulk, or capable of flying, or anything over the top! A Wonder Woman who is better than any other human being at combat (of any kind), plus is capable of punching through a steel door or running down a car going 40 mph, is more than super enough. The fighting ability alone makes her terrifying, and that's also the one "super power" they should emphasize above all others. She doesn't need to fly, or lift 2 tons, or anything really really "out there."
- Instead of slavishly reproducing all the old stuff from the comics, include a few things, but changed to make them a little less "comic book". In other words, try to at least ground the movie in reality a bit, like Christopher Nolan did with the first Batman film. For instance, instead of the wrist bands, give her a small Incan-style buckler shield and short sword, and instead of the "lasso of truth", give her a set of bolas (Incan "ayllo") made of braided vines taken from a hallucinogenic plant. Maybe she creates it herself while in Mexico and uses it to stupefy a few foes, only to lose them for the rest of the first film.
- So what's the plot? Origin story, obviously, but here's another idea to fill out the movie: the "awakening" happened due to an ancient temple of her ancestors being unearthed and plundered. The majority of the movie's running time builds the idea that the temple is in Mexico City someplace, with mentions of the temple being buried under "a major metropolis".
- The Twist: After fighting her way in to the Mexico City site, Wonder Woman learns that the Mexican temple was only a source for a map pointing to the MAIN temple of the ancient kingdom... in Dallas, Texas. Suddenly the audience that didn't care about some sort of danger to Mexico sits up and realizes that the climax of the film takes place right in the middle of a major American city.
- The Stinger: every superhero movie needs one now, for better or worse. The after-credits scene reveals that the evil genius whose company was trying to steal the power of the Wonder Woman was funded by none other than...
"Mr. Luther isn't going to be happy about how this turned out."
The overall feel should be of a fierce, possibly crazy woman who's incredibly good at fighting and is out to stop an evil corporation from exploiting her ancestors and destroying a major American city in the process. The movie should be less about cool super-heroics, and more about fast, amazing hand-to-hand battles as she fights her way across Texas, Mexico, and back into America. Our hero isn't a cute brunette in spandex, she's an attractive but dangerously fast and capable fighter who is a certified bad ass.