More like allowing the aircraft to fly the procedure in RNAV / LNAV, but monitoring the raw data for "comfort" (my aircraft doesnt have a nav display.) In terms of risk, there's no diference from allowing the A/P to track a VOR radial, as long as you ensure that he raw data has primacy. Also, where those waypoints may be based on NDB radials, the GPS makes a much better job of track keeping than me and my dipping ADF.
I agree that it won't work well for all procedures, but if something is that high in technical merit it should be designated as a PRNAV procedure. And we all know that manual construction / editing of them is a no no.