what you suggest would be trivially obvious except that it isn't quite
by the time we get anything that new installed, it had better be able
to go a lot faster than OC12 or we'll be right back in the same pot
on the day we put it in service.
Native packets over SONET is indeed The Right Thing To Do.
The more interesting question is what is the difference between
switching and routing, and what is the role of each as the networks
grow in size, capacity, and bitrate. (And no, I don't mean cells.)
It is fair to say there are both technical and religous positions on
this topic. (grin!)