I don't know that that would be necessary, although it's being done all the time for a variety of purposes anyway. I think the major problem is that of most RPGs: How many hits you took and dealt, what injuries you did, what spells you cast, who and what you killed.... all that is easy to quantify for purposes of giving experience. So an RPG designer can fairly easily draw up a basis for XP guidelines based on it, and a new GM can understand it. What's harder is thinking up XP guidelines based on a player's contribution to a story that the person making the guidelines has never, nor will ever, hear.
Well, XP by injuries, critics, and hits is another thing of RM that isn't pratical.
Hits delivered, crits, etc.
Too calculation. I think that rigid XP guidelines isn't very necessary.
The GM assign every player XP as he feels appropriate.
In addition XP are an overall experience/knowledge of the PC. Giving specific XP for combats it's a way to kill the "Role" part of the game, IMHO.
About the shield probelm:
I do some medieval fight, with arms and armor.
Shield is used as active weapon. You should intercept a blow and "drive off" the energy.
Leaving the shield in place, especially with light shields, mean a broken shield and arm.
Imagine a buckler that try to block a warhammer.
In addition shields straps are made so, when your arm is up (at chest level), an guard, you shiled cover you body, and you can "move" the cover.
If you relax you arm the shield will go behind you, leaving room for the blow and a running stance.
Using a shield well is a very important thing of a medieval warrior.
In RM this isn't factored because a shield skill means double DB and this, of course, will blow the OB/DB system.
Or better, will blow the warrior / monster system. Since many warriors will use a shield the system will rebalance itself.
The other problem is that only with a shield you could hope of block an arrow.
Now also this is an important skill.
BUT, if you don't have sword in you hand you couldn't improve your defense. So
The facing problem is a false problem. An RPG must be fast and giving facing in a 10 seconds rounds will do nothing in sense of realism.
So why don't punt a -20 (or -30,40 or whatever) DB for every attacker over the first?
I use a system where the breakage rules are very important and adds an element of unpredictability to combats. I use them. I enjoy them.
Why don't use a more simple system in RMC?
In case the blow is parried (no hits delivered or 5 or less hits deliverd) the defender weapon do a breakage check. If failed the weapon will suffer a damage (to STR) equal to difference.
If passed the attacker weapon do the some check.
The active defense. Not much to say here. Many think that an "active" defense will slow down. I don't think so.
A defender that roll a defense is actually playing is round.
If you put in game the fumble possibility of the defender or attacker, it's a very nice thing to play.
In addition you defender beat attacker of an X factor, a counter attack can be gained. But this is an advanced option.
About the table to be different but too similar. It's a delicate issue. In effect only against some AT there are differences. All in all you give a A,B,C,D,E criticals more or less with all weapons (even fists). Even with a cannon ball you will deliver an E critical (or n crits on the some location
blasted ribs, destroyed ribs, pulverized ribs, chewed ribs, etc.)
The mean of all of this is:
A charging knight on a heavy war horse hit a nearly naked bandit, hits for an E critical..
A kid will crawl behind a nearly naked bandit and, with a knife, hits for an E critical.
Now... who is potentially more killer?
The lance, only because score a critical at 87 opposed to the dagger at 95 and differences on dispositions of criticals.
I've taken the two opposite weapons with lower AT.
We found that a Battle Axe, Two-Handed sword, Flail and Lance are practically equal. And smaller differences with other weapons.