time based separation is actually nothing new
Wait around long enough.....
That been said Time Based Separation as now envisaged is part of the SES and SESAR.
Aircraft will be given a time to cross a given point +/- a parameter.
Long term it is believed to be part of the solution to some of Europe's capacity issues.
Once all aircraft are suitably equipped
.
The roll out of ADS-B above FL285 is another part of the grand plan.
Biggest difficulty for ATCO's will be during mixed mode operations.