Just a thought what happens when the all singing and dancing kit in the aircraft packs up when there is some kind of problem, you need a priority approach and ATC have no idea what anyone is doing any more?
You clearly need ATC in control (and in control of whatever computers are managing flight paths) but not wrestling with the unneccessary task of maintaining separation. Nor playing an artificial game of not touching the sides of airways. Nor trying to pass information intended for computers (FMCs and autopilots) in the bizarre format of human speech.
Automation of the en-route phase should not be bundled with the problems of terminal area control, which is much more subtle as there are real capacity constraints rather than the artificial ones imposed by controlled airspace limits.