The main problem as far as I'm concerned is that armour reduces damage from horse bumps by a lot. Which doesn't make sense. I can understand armour proecting you from a strikes blah blah blah that all makes perfect sense. But getting hurt by being thrown violently to the ground by a massive animal is something else all together. Horse bump damage needs to be reduced and needs to bypass armour rating.
Also on a personal note. I've been run over 3 times by cars and I've been lucky enough to come out of all of them with no injuries. One car ran me over when I was 6 while I was crossing the road, it was doing about 50kmph. I got thrown through the air and landed on my knees and some how only got scratches on my knees. The second time I was about 10 and a car came up behind me while I was on my bike and ran me over, I got hit by the bumper and thrown over my bike as it got sucked under the car and destroyed. I cat rolled the landing and didn't get hurt at all. The 3rd time I was riding down a hill when I was 15 and a car drove out of its drive way very quickly (the drive way ran almost parralel to the street so the car came straight out on to the street facing me) and got onto the road and was doing maybe 20 when I slammed into the front of it and bounced of the windscreen, again I didn't get hurt.
Now admitedly that was all luck, I broke my left arm in a fist fight and blew the cartalige out on my left knee falling off a bike going about 5kmph. And it proves very little, but it does demonstrate that being thrown about doesn't = DOOM.
Also the point about the shield isn't that the SHIELD is reducing the damage, the idea is that your facing into the impact, bracing and then taking the fall properly. Crushing some doof running away should deliver more damage than hitting some one thats ready for it.