IMHO: it's near and inevitable future.
All aircraft in the sky are in same network, sharing with it (and each other) wind/turbulence/icing/weather radar info.
Scenario: CPDLC>CPDLC (where first C is computer)>CCDLC. for a/c without DLC automated voice speech could be used.
Human controller can't issue two separate instructions at the same time. Computer can. infinite number.
What we will have: ultra-precise horizontal separation on final (multi-instruction speed control, or uncommon speeds 162, 157, etc), lower delays, marginal fuel savings, possible use of Optimum Flight levels (like a/c will fly 3 minutes at 330, then 3 minutes at 331, 3 at 332 and so on).
computer is able to do ATC stuff way better than human. but not yet)