#42 Won't ya just stop ?
You need a horse to move and a horse to stop. He has to know these 2 actions if nothing else.
If your darling has a sloppy stop- do the walk/stop exercise.
Ask him to walk 3 steps then ask him for a complete stop. Ask for a walk again, and a complete stop. The stop should be about 2 or 3 seconds long. Keep doing this until he's perfect. This gets him to focus on you and listen to you. And, he starts to listen and wait for your style of "whoa" because he knows it's coming.
After he starts doing this perfectly, practice this at the at the trot and later, the canter too.
You'll be pretty surprised at how good he gets when you say "whoa".
BE CONSISTENT - you want a complete stop.