By AC graphics (including -and especially- modern renders of her original outfit), I think she's one of the prettiest video game characters around. And I liked her before in lego graphics based on personality alone. So, were she real, I'd be more than happy to take her off Cloud's indecisive hands.
But as for the perception, yeah I dunno. Lulu's got some massive boobs that are ready to pop out of her dress at any moment, and people don't seem to treat her the same way, so go figure. She doesn't show as much skin I guess, and it would take an inordinately long to time to get between her legs.
@Tifabelle:Reeve probably had sometime to do with it. Also, as I said, Edge houses people from the Plate too, so there were people with money around.