One of the first things I noticed when listening to Jeri Ryan in interviews is how significantly different from 7 she really was. Ryan is bubbly, personable, and one chick I would love to hang out at a bar with on a Friday night. 7 is stoic, serious, and not the best of friends. I think that added to the talent that was Jeri Ryan in portraying her.
Yeah so she was called Barbie of Borg for so long and you had the catsuits, but if you still believe that, then I think you missed the point of the character. There were so many layers to 7 of 9 and in retrospect, bringing her on might have been the best thing to happen to the series. My only problem was it came at a character's, I liked a lot, expense when they could have easily gotten rid of either Neelix or Kim instead.