btw, the way I keep from getting instructor burnout is by activly flying competitions. The funny part about this is that at the rate I'm going, at the end of this season I'll have lots of hours in competitions, and lots more doing instruction, but not much of anything else. Still, I find both fun, so it works for me :-). And they are both really different.
More to the point, when I talk to new students, I am always clear that I personally won't always be around if there is a contest that is conflicting. We have several other instructors, so it's not a problem there.
On the "system" end of thing, we are pretty loose at my club, at least right now. A little bit ago I got talked in to accepting the "Cheif Flight Instructor" title. The system was working pretty well when I took over, so I haven't felt a need to change anything. (The prior guys did, in fact, get burned out)
But a lot of it working is due to the guys who show up and make it work. It certainly isn't anything I'm doing personally.
There are a couple of guys (and one in particular) who are experieneced pilots who don't like to instruct and won't take the buddy box, but what they do is pre-flight, repair, inspect, trim and tune and all that other ground stuff. It's great having them at the field. I've been able to bring a student back to the pits and just tell the guys there "needs more aileron and less elevator" and know that when this students turn comes around again, he and his plane will be all set to go.
We seem to have a really great bunch of students and instructors right now. Even the guys who might be perannual students are easy going about it, I don't have anyone that is hard to deal with.
On loops and rolls and stuff, I haven't had that problem. I've usually had to convince my students that a loop now and again is OK.
But I do use it as a way to really push controlled straight and level flight with controlled turns in between. I won't let them loop until they show me they can get themselves straight and level and hold a constant altitude around the pattern. The biggest thing I push is being smooth on the sticks, espeically with landing approaches.
On test flying, I try to get two sets of eyeballs on the plane before a test flight, mine and one of the guys mentioned above. I haven't lost or seen anyone loose a trainer on the test flight at my field. I have grounded a couple as unsafe though. I have my own beat up trainer at the field that I will frequently use if a students trainer is grounded, just so they don't have to go home disappointed with no stick time.