Hi Guys, I agree that you need to know how your GPS works, but you should also need to know the basic dead-reckoning and waypoint navigation techniques, as well as radio nav aids.
I used to think that too, and I still agree that the basics (dead reckoning, map reading, leg timing, lost procedures and such) should be taught as always. But I'm not too sure about radio navigation aids anymore.
I was taught on a full-IFR, 1970s panel. ADF, two VOR/ILS/DME. One of the VOR/DMEs was actually an RNAV box where you could transpose the VOR/DME to some other location and use it from there, if you know what I mean. I've never seen that box since.
I was taught, and am still able to use, all that equipment. But the times I have used radio nav for real in the last years can be counted on one hand. There are virtually no en-route NDBs anymore, and VOR/DMEs are few and far between, and not always in convenient locations.
I also find that the aircraft I fly tend to have less and less traditional navaids, but all tend to have panel-mounted GPSs now. Mostly Garmin 430s at the moment, but other types are also present. The aircraft I fly most has only got a single VOR, no ADF, no DME. And the VOR is essentially only used to listen to the ATIS (which is on the VOR frequency at my home base), and to set the runway in use on the OBS ring as a reminder.
So I would not cry over radio navigation being moved to the IR syllabus, and the PPL syllabus concentrating on manual, basic navigation techniques, augmented by GPS.