As far as breasts go, this really isn't all that bad compared to most women in games these days. They aren't HUGE, and she's not exactly dressed up like any number of other characters I could name. Hell, Tripitaka showed off more boob than this and she was supposed to be based on a Buddhist monk.
If anything, I get a Jade from Beyond Good and Evil vibe from this character. Yeah, she's sexy, but it doesn't really feel like titillation (teehee...tit) I actually think this is one of the better heroine designs I've seen in a game in a while, and I think she's certainly got a lot more going on for her than just her breasts.