Your right, the more handle on these dogs the shorter you can make em if you so choose..The other side of that is, I have found a lot of folks dont know how to get a cur dog to going yonder and think that all cur dogs hunt short or they got a dud when in reality, it's their lack of knowledge and knowhow hindering that.
I'll admit..I'm probably the poorest dog trainer on the planet. That's why I raise the dogs that I do, so that I don't have to be good. I don't care how good a trainer or dog-man is, there's no way to ever overcome poor genetics.
I've personally never seen anyone "train" hunting drive (or brains for that matter) into a dog that wasn't bred and born with it.