Two Combat Rules

I have had 2 thoughts about combat rules to add to the pile, they aren't in the first combat draft, but might be interesting to add:

1) Shield Sacrifice:  I found this rule in the "Fight On" old-school fanzine and we used it in Return of the Trolls.  With this rule, if you are hit you can call a shield sacrifice, which will cause your shield to break to pieces, but it will stop the damage from that attack.   It was nice in one sense, but was a little too disproportionate.  Perhaps we could either make a shield sacrficie reduce the damage of a hit in half, instead of stopping it completely, or perhaps limit its use to Fighters, Paladins, Rangers and Berserkers with class and level.

2) Knockdown/Knock Back:  to make combats a little more dynamic, perhaps we could say, any time a
"natural" 15 is rolled and the attack is a hit, the target (or equal or lower size to the attacker) is knocked down.  If a "natural" 15 is rolled, and it is a miss, or the attacker is bigger, the defender is driven back 1 inch.