Eh, 1) I find it hard to believe that Wonder Woman or Supergirl are the holy symbols of feminism, they're comic book characters; 2) I don't see the problem with something being "sexy" and a positive symbol for people. We are humans, as humans we have sexual drives and desires. Accordingly, we tend to cast everything in sexual lenses for both men and women. There's a reason Pres. Obama made sure those photos of him shirtless, coming out of the ocean were everywhere. Individuals viewing Pres. Obama as a sexual object doesn't diminish his position as the leader of the free world.
Sex is not evil, "objectifying" an individual isn't either (we're all sex objects), the context of sex or sexualization does matter to me. I'll use the character of Quiet in MGSV as an example,a scantily-clad, big boob, bikini-wearing sniper that doesn't speak. Now, overall MGSV is an ass written game and honestly Quiet is the only "character" in the game in that she has an arc. However, she's still a shit written character that is made specifically to pander to male gamers in an otherwise "serious" game with a "serious" story. If you want to make some weird softcore MGS spin-off then go ahead and make a character like Quiet but the context in which that character is presented within that game MAKES NO DAMN SENSE and is insulting, in addition to the other troubling aspects surrounding her character.
Sex itself is not bad, however the context it is presented does matter.