I too love the OP, and don't find it very 'rantish' in the least; thought provoking, sure, but a rant? I guess if I saw myself "stuck" in a rut with any horse I might see it that way. But I love finding those things that bother the horse and figuring out a way to get them over it. Or finding those things that the horse just isn't that good at, and working on getting better at.
Even every day "stuff" can help your horse become better; The other day, I'm at the barn cleaning my mare's run, and I have her on a lead, and she is walking with me while I haul the noisy clacky cart around to clean the run and haul shavings. One lady commented, "well that's one way to get her some exercise!" If I have tedious stuff like that around the barn to do, I will usually put her halter and lead on, and she'll join me while I do what I need to do. Gives the horse a ground 'job' persay, but also gets him used to all sorts of nonsensical 'stuff'. Keeps those ground manners tight, as well, since your horse will have to be well behaved in order to help do those barn chores!
One of my other favorite things to do, is when something someone does scares a horse I'm working with, and they apologize, I tell them, "that's okay, do it again, and keep doing it til I tell you!" The look on faces is priceless, and I usually have to explain why... The only exception is when I am doing something with a horse that IS dangerous (like trimming feet, or what have you), then I do get bristly if someone comes around and does something stupid, but I will still usually work through it if the horse spooks, since I ultimately want a quiet horse, not one who is all tense and stupidly concerned about everything going on around him all the time.
Same with undersaddle; something bothers him? Well, keep doing that task until it doesn't bother him anymore, like the OP mentioned with his Appy and the rope. My mare was goofy the other day about being touched on her butt while I was riding...so I kept rubbing her butt until she fell asleep, then asked her to walk on, and continued rubbing her butt; she got over it, and she wasn't frightened, or forced into it, I just kept rubbing until she didn't worry anymore.
It's about transferring a horse's thought process from the reacting part of his brain to the thinking part...sometimes it "looks and feels" like it might take forever in a session, but just keep going; wait for that subtle change that indicates "Ah Ha! I get it!!!" It Always comes...
I can't tell of all the times when having a well mannered horse has saved my butt, simply because the horse was trained well enough to know to listen to my cues, regardless of circumstance. I had one really scarey trail ride this spring that could have killed both my mare and I had she not known a solid stop; but even though her rear legs were caught up in barbed wire (didn't see the wire as it was buried in grass, and all I heard was a 'whoosh' sound as it got caught on my horse), she still stopped from a working trot, and stood like a rock while I untangled her legs one by one. I still look back at that day and think about how it could have ended if I wasn't so diligent in how I train.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."