Hi Maureen --
I agree with you 99%! The one thing I thought of as I was reading your post is that, sometimes, when we "use what works" in one setting, if we're not careful about whether or not that conflicts with another "thing that works", then we might be setting up for confusion down the road.
Here's my example: I never felt that I needed an "out" -- I just used my body position and movement and, if I needed an "out" for, say, a tunnel/A-frame discrimination, I would bring up my opposite (outside) arm, which turned my body into my dog's line, and she would take the farthest obstacle of the discrimination. It worked -- so much so that I had very consistent discriminations with my dogs. What I didn't think about, though, is what other ways do I use my "outside" arm? Well, most of us use the outside arm for switches. So now I have unknowingly (unthinkingly) created a conflict in my handling. Does bringing up my outside arm mean "switch" (turn away from me by >90-degrees, on my index card!) or does it mean "take the farthest obstacle in a discrimination"? I learned that Mia's definition was the "turn away from me by >90 degrees" -- at a trial where we were spot on for a bonus line Regular run, with only a tunnel/dw discrimination and jump for the home stretch. Mia was doing a beautiful arc of jumps at the far end of the ring that led to the tunnel/dw coming up the side and, as she headed for the jump just before tunnel/dw, I brought up my outside arm as I had learned was successful for such discriminations -- -- and Mia cleared the jump and then made a very nice 90-degree turn off of the whole discrimination and over some tunnel bags that were resting against that side of the ring.
THAT was a lesson well learned -- When I run her closer, my outside arm turns me into her line and she picks up that pressure toward the outside obstacle. Doing that at 80-feet away, she mostly only sees my outside arm come up and so she does what she knows an outside arm means. Now I try to reserve my outside arm only for switches and avoid it for the outer obstacle of discriminations.
This is a long story -- I really just meant to say that I agree with doing what works for our dogs, but in doing so, we still need to analyze how it might fit into all of our communication with our dog. I guess that's ultimately the purpose of a "system".