My theory (and correct me if I'm talking rubbish) is that a slightly slack headtube helps you steer more smoothly (it takes a bit more effort).
A slack seattube puts all your weight on the saddle so you're not leaning down on the front wheel even when you're on the drops
This makes it loads easier to get all your weight on the outside pedal and steer smoothly through a corner.
Many modern road bikes have steep crit-like geometry which makes them rather skittish and precarious with so much body weight on the front wheel.
^ +1
My theory (and correct me if I'm talking rubbish) is that a slightly slack headtube helps you steer more smoothly (it takes a bit more effort).
A slack seattube puts all your weight on the saddle so you're not leaning down on the front wheel even when you're on the drops
This makes it loads easier to get all your weight on the outside pedal and steer smoothly through a corner.
Many modern road bikes have steep crit-like geometry which makes them rather skittish and precarious with so much body weight on the front wheel.