Disc's are the future just look at Colnago's most high end road bikes now with Disc brakes. The only reason road bikes have not has them up until now is because rules for racing never allowed them but that's changed.
A lot of development is now going to be put into them for road bikes making them lighter and more compact. As these new developments are made disc's of current grades will become cheaper and eventually all but the lowest end bikes will have disc brakes.