RE: Test flying
It seems you might be hitting on a politically correct, ego driven, nerve here. I was blessed when I learned because everyone wanted to help. There wasn't a "pre-ordained" instructor. At some of the clubs I'm a member at, some of the instructors are out of control them selves!
It should be emphasized, that it is a flattery to you when some one comes and asks you for help. This person asking for help cares about his investment not only in the "hardware" but in the actual learning how to fly.
Not too many beginners come and ask me for help, now-a-days. Maybe its because I'm only flying jets now and they can intimidate anyone, however, I love to help other people become successful and acquire safe flying procedures.
I think the solution to your problem would be to continue to have dedicated instructors, but make it so that everyone can help every one!! Not just instructors.
Raf