And why do you feel that female characters are less deserving of slots?
Besides, we're looking for new characters, not Rule 69ing the ones we have.
There are not that many characters in the DC universe who deserve to be in a fighting game with limited roster and DC comics are the main reason for that.
Why?
Because DC comics always had their big 7 (Superman, Batman, Wonder Woman, Martian Manhunter, Flash, Green Lantern, Aquaman).
These few characters and then they started ripping their own characters off and coming up with new characters, but who were basically the same characters with other personalities.
Why?
I guess DC was thinking "never change a winning system" and because of that we're not stuck with:
Superman > Supergirl > Superboy > Power Girl > Krypto, the Superdog > Superhorse, Supercat, Supermonkey and so on...
Batman > Grayson Robin > Todd Robin > Drake Robin > Wayne Robin > few other Robins > Batwoman > Batgirl > many others...
Wonder Woman > Wonder Girl > Donna Troy > Artemis
Martian Manhunter > thank God there is no one else who is even worth being mentioned (fuck Young Justice)
Flash: Jay Garrick > Barry Allen > Wally West > Bart Allen > Max Mercury > Few other Speedsters > Few Speed based villains
Green Lantern: Alan Scott > Hal Jordan > Guy Gardner > John Stewart > Kyle Rayner > Few other Green Lanterns > Few other Lantern colors
Aquaman > is the worst of them all, because of all the various kinds of goldfish and dolphins that come together with him...
So with such a way of introducing characters, how many female characters do you see being in the game, if we already have the exact same character in the game already like for example Superman > Supergirl and Batman > Batgirl.
Them just being female characters shouldn't justify having them in the game, because they're simply inferior to their counterparts; in terms of marketing-success, representation, abilities, popularity, simply everything.
You would have to dig deep to come up with female DC characters who are relevant enough to be in the game and not to steal spots from higher demanded characters.
Why having Poison Ivy in the game if more people demand Martian Manhunter? Why having Poison Ivy in the game, if the roster is already full with Batman characters and Swamp Thing could add far more obscurity to the roster?
Why having Killer Frost in the game, a character who never mattered in comics and was mainly a villain for a superhero that basically even many regular comic readers don't know / don't care about, if you could have Captain Cold in the game who fulfills the task much better?
Marvel comics > DC comics.
Marvel has actually a lot of female characters who would be great for a game.