Tinstaafl,
If Pall wants Doppler NDB's, why not.
We might also try log periodic antennas, time division multiplexing,
frequency shift keying and even tweak the Pulse repetition rate.
Concurrent with the Doppler VOR program, there will be both a phasing out program for some NDBs,
and an enhancement (power boost) program for others.
GPS RNAV approaches will progressively take the place of terrestrial navaids, particularly in remote areas.
No mention yet of any policy to implement WAAS augmentation for the GPS equipment.