Er, having a properly sized cockpit where your body is positioned and balanced properly will avoid excessive pressure on your behind by balancing it with pressure on your hands. If you need drop bars todo this, your top-tube is probably a bit short or handlebars too high or something is off with the fit.

Drop bars are good for getting a little more aero, but aero bars are better at that.... so flat-bars with aero bars might make a good commuter!