IO,
Regarding GPS training, I think the present scheme of navigation should continue to concentrate on the basics of DR but the individual should be encouraged to make use of modern aids where available after PPL qualification. Otherwise, it will only increase the cost of the licence. Also, if the use of GPS is introduced too early, human nature being what it is, pilots will undoubtedly rely on it too much and not become proficient in the basics, which may have the opposite effect to that required.
An "add-on" training scheme post PPL, maybe; such as the "pass-plus" for driving might be a way forward. Trouble is, there are so many different types of GPS equipment; from my own experience, the most difficult part of GPS is working out which buttons to press to get the desired effect to appear on the magic box!