I think the vast majority or instructors do a good job. If i think back to my PPL training i think it was pretty awful and have similiar comments from others who also trained in the late seventies early eighties.
I can remember hardly ever having any ground briefs, the qualify XC dual route was flown by my instructor whilst i read the map, hadn't got a clue what to do if i got lost, other than i was pretty good at map reading which ultimately is what you need to navigate. Diversion? Whats that!
If there are hazy areas, its either lack of experience or confidence in certain maneouvres, stalls/spins. Let a more experienced instructor cover these lessons. A 200 hour instructor is not going to have the same confidence as a 2000 hour instructor. Its up to CFI to take the less experienced under their wing and help them, not knock them by saying they are crap.