Exactly. Yeah, they're pretty hot girls, but they don't look like heroines from a novel, unless it was the literary equivilent of a cheap porno movie with steampunk aspirations. It does irritate me when female action heroes are dressed like prostitutes. It's not that they look "sexy". It's that it's just so bloody impractical. I mean, seriously, no bra? Whoever thinks not wearing a bra is a good idea when you're duelling people and chasing bad guys has obviously never had occasion to wear one. If you're anything more than an A cup, physical activity is decidedly uncomfortable when bits of you are flopping all over the place.
And.... HEELS. Just NO. Stick your female protagonist in some flat black leather biker boots - it'll still look awesome, I promise, but then it will actually be plausible that she can do a decent pivot to side-kick the monster in the solar plexus, or it's spaceman balls.
Clothes for this sort of character should allow freedom of movement [so not head to toe PVC, I'm looking at YOU Kate Beckinsale*] not have excessive material that could be grabbed on to, have non-crippling footwear, and supportive underwear. Come on... that's not too harsh a list. You can easily make an outfit that ticks all those boxes look good on a good-looking girl.
The Tomb-Raider get-up isn't too bad - a vest, shorts with a belt and pockets so she has somewhere to put stuff, and hiking boots. And she still looks hot.
I think personally I'd dress a character a bit like a ninja - in soft, figure-hugging black material, with the aforementioned biker boots, possibly a utility belt, and a cropped slightly retro black leather biker jacket. Yeah, the leather might creak a little, but hey, nothing's perfect.
*OK, I admit she looks awesome in Underworld. I can't help thinking though, that outfit has got to stink by the time she takes it off...