As much as she can in a skimpy pink bikini.
Its just an added design to make her look more girly I guess. it not gonna affect gameplay in any way. unless you have to learn her walk mechanics else she twist her ankle.
The bikini was supposed to be a cool revelation at the end of the first game, and carried on in a "mission's over, lemme get into something more comfortable" tradition. I mean, if you went through all the crap she goes on a mission, when you went back home, you'd take a big shower and stay on your underwear lazing around for awhile, right?
And the skintight suit, as long as it works logically, would actually be a tactical upgrade for her in certain conditions where she has to move faster. We've only seen her use it in one mission so far, and it wasn't exactly because she had a choice. The Zero Suit allows her to move a bit faster and more freely, unlike the arsenal she always carries along with her. The material it's made of and the way it moves might even aid her to move instead of restricting her.
But high heels? That's the only design choice so far made for the sake of pure asthetic, and completely useless when looking at it from a logic standpoint. How are high heels going to help her in any way?