I'll point out that Rick doesn't use flooding. Not with hobbling either. He uses sacking out for that, too. The point to him is to NOT get a reaction from the horse. He's different from for example McLean. Rick also doesn't
I'm not 100% for Rick's methods in every scenario, but for some things I do use negative reinforcement (like with yielding), but for different things (like lifting feet) positive reinforcement WITH negative works the best.
Bissen used to be shut down when I got her, so I too know horses like that. I'd never want to take away the confidence, curiosity or spirit from either of them.
I watched a video where Rick sacks out his mustang stallion to a flying helicopter (remember, the horse was chased by helicopters when caught).
He was in the saddle the whole time, and it was really nice to see how he let the horse figure out for himself, that he didn't have to be afraid. He "forced" (as much as he could with one rein in a rope halter, holding a camera in the other. I'd rather say "encouraged") his horse to face his fear, and taught him to think for himself, let him figure out that it won't hurt him. I don't think anyone believes it's possible to sack a horse out to every single thing in the entire world
Rick's point in being sacked out is that it builds confidence between you and your horse. Your horse gets more and more certain that when he's with you, scary things won't hurt him. That's his main point. He wants the horse to come and look to him when it's scared. It's exactly as you describe your relationship, Ulrike