Having recently watched a presumably overloaded commercial flight (ME piston) climb only about 500 feet some 5nm after departure, it should come as no suprise to me that there are commercial operations which rely on the ADF needle "especially when adjacent to lumps of rock", but I hope that I never end up sitting in the back of one of them, Croqueteer.
If you really rely on the ADF needle "especially when adjacent to lumps of rock" then presumably you don't carry an EGPWS either.
I agree that every bit of situational awareness helps (and I use the ADF needle on the RMI too) but IMHO you are just trying to justify some of the dinosaur hardware that is still flying "commercially". Of all the stuff one can screw into one's panel, the ADF is the last thing I would rely on for obstacle clearance.
Dyson - the proposal, AIUI, is to do away with the mandatory ADF for IFR in UK CAS, which is basically airways flight, and you can't fly airways without BRNAV capability, which in the GA context means a mandatory IFR GPS. In Class G, it won't worry you.