Don't hate on Yuna (yet)

I get that the author draws her like a typical fanservice female character - huge boobs, tiny waist, pretty face, etc. However I don't think it's right to hate a character for something she has no say in. The only valid reason to hate on Yuna so far is that she has been pretty much useless in all of the fights she's witnessed but what can she do when even the Dokgo brothers who outrank her haven't managed to beat anyone? Female characters are humans too; they fail sometimes and they aren't always badass. However I do expect some growth in her fighting capability and her role in the story; after all Pietro has agreed to teach Yuna which means he sees some potential in her, and the most important thing is that unless Yuna becomes stronger she'll become a burden to the MC and another weakness of his which the antagonists can exploit (and officially end up in the bottomless pit of 'useless female characters in action comics'). I'd prefer Yuna become a valuable ally to Pietro. People hate on Yuna 'cause she's weak but let's not forget she has the guts to lie to Nathaniel (one of the 'disciple' killers) even after he's broken her wrist and threatened her. She also comes up with the kidnapped boy's location on her own (in the amusement park arc) although Pietro has it figured out too.
I'd love to see some of the supporting characters' backstories as well, such as Jiwon's (the blind informant). I want to know how she goes blind and why she's ready to help Pietro without as much as a second thought. It's boring when everything revolves around the MC and supporting characters are treated like disposable plot points instead of being properly developed, which unfortunately is the case for a lot of action comics. I also hope to see more of Choi Eunchang, the president of that huge weapon manufacturer. Pietro saves the young Choi Eunchang's life, and he seems to remember that favor well, so it would be foolish of the MC not to use this connection to his advantage.