What's that got to do with her skintight bodysuits and being Borg/part Borg? I know the tried to explain it inshow by helping her heal after some Borg implants were removed but after a while that excuse was just superflous.
Let's face it.. she was eye candy for male audiences, especially teenagers, whom the producers considered their core demographic. When the ratings started to drop their solution was to sex it up, plain and simple.
As i said, it would have been cool to properly induct her into Starfleet after a season or two and give her the uniform. It would show character progression and integrate her even more into the crew (and allow Ryan to maybe eat a Burger once in a while

)
It's just one of the things Voyager missed to become a unique show and find its own style, as it stands it was just a lesser cousin to TNG when it could have taken Trek to a quite different path.