7 doesn't think about such things, her uniform choice is based purely on comfort. Having fabric flapping around and loose distresses her after years of borg plating, she likes to feel contained.
So, next time you feel embarrassed about 7 just remember what she's been through and stop thinking about yourself.
You are right. I had not thought of it that way before. Also I think her character added to the show. TOS had Spock, TNG had Data and Voyager had it's SOV. All beloved members of the Trek family.