Reb, I know how you feel about your abused horse. We adopted an abused pony when he was 7. He's now 16, and still skittish as all get-out. The first time I ever attempted to lunge him about a month ago resulted in him panicking and running around the pasture with the lunge line on for 10 minutes before I was finally able to calm him down. Needless to say, he will now be trotted in-hand by his halter, because apparently holding on to a lead rope a foot from his face is terrifying, and sent me into the dirt.
He's very obviously abused. He does trust me the most, but that's not saying much. I can go up and catch him(I used to not be able to a couple months ago), pet him, do his feet no problem. He does NOT like farriers, and he does NOT like vets. The vet was just out for shots and coggins, and he had to be twitched. He swung his butt into the vet twice, and cow kicked him in the calf. After they were done, he got as many pats as possible. He doesn't like strangers, either. He will take off at the sight of a stranger. He used to freak out at just the sight of a whip. I've gotten to the point where I can rub the whip over him and he doesn't have a heart attack. We've never used a whip on him, and never will, but it's a good desensitizing exercise.
There on the tips of fair fresh flowers feedeth he; How joyous his neigh,
there in the midst of sacred pollen hidden, all hidden he; how joyous his neigh