lets be realistic... they are so much more flattering on our legs with a pair of heels... dont get me wrong i LOVE my skinnysand rarely wear anything else, but a bit of a boot cut/flair also can look very sexy!
I never used to be able to find good jeans... until skinny came in. I'd be upset to see skinnys go. Flared / bootcut look amazing on a lot of girls, but for me I always find that they're either too loose or too tight on the hips; and they stretch more around the waist and fall down as a result (whereas skinny jeans don't fall down because they're tight everywhere else.)
I'm happy for jeans that are skinny / fitted for the most part but with a bell shape at the bottom. I think that's a good balance.
I'll just add to that that I do think it's quite likely that the shapes and cuts of bootleg / flared jeans will have improved since the skinny jeans trend to be more well fitted. I will be interested to see if that's the case.
Generally speaking, I believe jeans are most flattering when you have a degree of vertical symmetry above/below the knee- that is why "skinny" jeans create the effect of short legs on bulkier builds and excessive flaring appears very odd.