Most builders at least used to decrease seat tube rake in the smaller sizes in order to decrease reach while avoiding foot strike. This isn't optimal either because it changes the rider's balance and causes more weight on hands. There's not a perfect way to do it. 650 isn't the solution either because there's so little availability both overall and during a ride. Woe to the 650 rider who goes through both tubes or ruins a tire. Personally, I'd take better balance and a shorter stem.