booo! I am old, unfortunately! 
there must be some trade off for the quicker steering/lower height? Cos otherwise, BITD they'd have gone for same?
you have to take into consideration the fact the most old school bikes were designed for kids to ride,
the average rider age now is way above what it used to be back then, consequently frames have grown too,
the low toptube i think is a tailwhip thing, it makes the bike feel less intrusive to me too,
plus most old school frames were designed by dads and company nobs etc, these days its all rider input,
hope that helps.
stylewise, i love the way new school bikes look in the same way i love the way modern cars look, i really like the old stuff but it'll always come 2nd best as its old/dead technology in my eyes.
