The Super Duty is constantly evolving. It has only a few things in common with the original (cab structure/doors). The Super Duty trucks help to keep the medium duty (F450-F750) viable. The Super Duty is more of a down rated medium duty rather than an uprated half ton, like the competition. I doubt you will see Ford basing their 3/4-1 ton trucks off of a half ton, or making any big changes until they loose market share or the feds mandate them to.