I'm a firm believer that a superhero movie is only good when we have a great here AND a great villain.
Agreed.
Of Wonder Woman, GL, and Flash, I don't know if they have any in their rogues gallery that would make a great villain on screen.
I think they all do.
I don't know any for WW, maybe Sinestro for GL,
WW's primary villains are Ares, Circe and The Cheetah.
Ares has a great visual, is the god of war, has an interesting personality and has what it takes to turn the world into WW III.
http://community.livejournal.com/scans_daily/4400456.html
http://community.livejournal.com/scans_daily/4038465.html
http://community.livejournal.com/scans_daily/tag/ares (Look at the links with DC's Ares)
Minerva's Cheetah has magic claws, stats to make her keep up with WW in combat, with some versions she eats people to keep her Cheetah form, is the polar opposite of WW since she was rejected by her god because she wasn't a virgin when she became his champion and her human persona is an evil Lara Croft. There's a great Rucka story about her when she infiltrates the jail WW is kept in when she is on trial by the U.N. after killing Max Lord. Minerva has a ot of depth in it. She seems to think she has a rivalry with Diana where she's envious about why the world treats her so well while she's hated. It shows almost like a rivalry between two kids fighting over who their parents, in this case the world, sees them from Minerva's point of view.
http://community.livejournal.com/scans_daily/5785133.html
http://community.livejournal.com/scans_daily/tag/cheetah
Circe's sort of like WW's Loki.
http://community.livejournal.com/scans_daily/5930679.html
http://community.livejournal.com/scans_daily/4321861.html
http://community.livejournal.com/scans_daily/4165320.html
http://community.livejournal.com/scans_daily/tag/circe
Other villains include Medousa
http://community.livejournal.com/scans_daily/4371479.html
Veronica Cale, she's kind of like WW's Lex Luthor. She's a self made billionaire who thinks WW's a hypocrite/fraud since she's a princess and given her powers by gods. I think her origin is revealed in Bitter Rivals.
http://community.livejournal.com/scans_daily/4365017.html
http://community.livejournal.com/scans_daily/tag/veronica+cale
and with Flash, I don't think a talking gorilla would be taken seriously,
They can go in two directions with Grodd. Either make it campy or do it really, really serious.
Grodd can be a very cool villain, he just needs to be done correctly. He will be tougher to adapt in live action then in comics or cartoons, though.
This is a guy whose got telepathy, is utterly ruthless, can create his own super technology, has a physique that is much stronger then an average gorilla and is a very intelligent villain who can competently use his abilities to their maximum potential.
http://community.livejournal.com/scans_daily/tag/grodd
and would probably make unfair comparisons to Planet of the Apes.
Comparisons are going to made no matter what they adapt.
In fact, I don't know if for a character like WW there is a great story to be told.
Gods & Monsters is a great story which would be great to see in film. That's only the beginning.
There's the Bana:
http://community.livejournal.com/scans_daily/4145718.html
Which leads into Artemis becoming Wonder Woman for a while after The Contest.
http://community.livejournal.com/scans_daily/tag/artemis
Theres much more where that came from.
Here are some great story lines from the comics you can read.
http://community.livejournal.com/scans_daily/?tag=when+wondy+was+awesome
At least with Ant-man, most people know nothing of the character, so changing the costume, or other aspects of the story won't upset people.
You're underestimating Ant-man. He can be a very complex and tragic individual. At the very least he created Ultron, whose brain waves are based on his own, and is very mentally unstable. This was covered very well in the Ultron Unlimited story arc.
http://community.livejournal.com/scans_daily/3202290.html
http://community.livejournal.com/scans_daily/3203611.html
http://community.livejournal.com/scans_daily/3205303.html
http://community.livejournal.com/scans_daily/3231111.html