I think it's important that we don't cling to the rules our mothers taught us "just because that's the way it's always been done." If your legs look better with hose, wear hose. If you find that brown and black is not a good combination for your skin tone, then don't wear it. Don't be a slave to fashion rules -- old or new.
My big problem with the leggings ban is it places the blame onto girls for being "distracting" instead of onto those who might be getting "distracted" spending all their time ogling the girls. The fact that no comparable rules were set out for boys shows that they think it's up to girls to uphold their own honour and fend off advances.