Great post Delete!
I had a mare a few years back (ok, 10 years ago!) that had the slowest, most comforable jog, but the second you asked her for a lope she broke into a dead gallop and there was no talking her out of it. I was 12 years old at the time, so didnt know too much.
My trainer told me that the way to teach her to slow down is to let her run. I was baffled. So for about a month, I only rode her in the indoor arena by myself (and with my trainer of course). When I asked for the lope, I knew she was going to just take off. My trainer said not to interfere with her. Don't pull, don't anything. Just go for the ride. When she started to tire out and naturally slow herself down, that's when my trainer told me to kick her and make her go. Not hard of course, but definitely start making her move faster and more forward. After a couple minutes of me "making" her run, then I would ask for the jog again.
This taught the mare that she was the only one forcing herself to gallop, not me. Its kind of a mind game.
Horses only will give you as much as you ask for. They are naturally lazy and will always take the easy way out. Once she figured out I wasnt asking for the gallop, she was happy to slow lope around all day long.
I know this is a western take on this, but the horse's brain works the same way regardless of what saddle you are riding in :)