I'll have to create a home page on Yahoo, or some thing some day to post these rules for all, but for now I'll give you an idea of my system which covers some of the concerns mentioned already.
One, it does not require charts once you have the basic system in your head, but it would be good if just the DM had it. The player would just put 3 numbers by each of the weapons his/her character has. "Longsword: 1/0/0" Thats it.
It allows for greater penetration of heavier armor with certain weapons without destroying the usefullness of light armor.
Any weapons smaller than "small" is treated as the "small" column.
The column to the left represents the modifier's to the various armor types based on the weapons size, usually vs heavy armor. Some times this number is stepped down a notch, or revesred for light armor. The bottom row is to particular armor categories regardless of weapon size.
Sword (slashing) weapons are good vs light, or non armored targets and get a +1 for the Light category. The Greatsword gets a +1 agains heavy and medium armor, but looses it's edge vs light armor types do to the greater unweildiness of the weapon due to size.
What it comes down to is you'll need to tweak these to fit your needs, but it gives you a standard to base all weapons on. These charts also keep the adjustments within a pretty tight range so one weapon isn't too uber.
* Slash Light Medium Heavy
-1 Sickle Small 1 0 -1
0 L Sword Medium 1 0 0
1 G Sword Large 0 1 1
1 0 0
In between slashing swords and blundgeoning weapons.
* Chop Light Medium Heavy
-1 H Axe Small 0 0 0
0 B Axe Medium 0 1 1
1 G Axe Large -1 1 2
0 0 1
* Blunt Light Medium Heavy
-1 Lt Mace Small 0 1 1
0 Mace Medium 0 1 2
1 Maul Large -1 2 3
0 1 2
Hafted piercing. (same as blunt)
* H-Pierce Light Medium Heavy
-1 Lt Pick Small 0 1 1
0 Hvy Pick Medium 0 1 2
1 Mattock Large -1 2 3
0 1 2
Thrust piercing.
* T-Pierce Light Medium Heavy
-1 S Sword Small 1 1 -1
0 H Spear Medium 1 1 0
1 Spear Large 0 2 1
1 1 0
Okay, monks get hosed a bit, but then again ... a fist at full plate?
* Unarm Light Medium Heavy
-1 Halfling Small 0 -2 -3
0 Human Medium 0 -1 -2
1 Ogre Large -1 0 -1
0 -1 -2
Wood, or other "soft" blunt weapons when comparred to metal.
* Wood Light Medium Heavy
-1 Sap/Whip Small 0 0 -1
0 Club Medium 0 0 0
1 G Club Large -1 1 1
0 0 0
Wooden Shield Light Medium Heavy
-1 Buckler Small 0 0 -1
0 Small Sh Medium 0 0 0
1 Large Sh Large 0 1 1
0 0 0
Metal Shield Light Medium Heavy
-1 Buckler Small 0 0 0
0 Small Sh Medium 0 0 1
1 Large Sh Large 0 1 2
0 0 1
My overall desire was for there to be a difference between weapon types and various armors. I wanted there to be a reason for characters to wield some thing other than a sword. (okay I know mathematically a 20 X 3 weapon is more or less equal to a 19 X 2, but ... from what I've seen the increased threat range is much better in actual game play)
I wanted a speck more of realism, but I had some game mechanic considerations as well. One, I opted for certain weapons to do particularly well vs heavier armor types without making light armor uselsss. (A couple of weapons do get a +1 bonus towards lighter armor types though).
Maybe it would be more realistic for plate armor to be nearly negligable against a two handed maul, but I also wanted to keep within the spirit of the "+2 to -2" circumstance bonus of the game which I did for the most part.
I also took into consideration how the weapons were used and against what armor types. Sword were great agains unarmored and light armor types. Thrust piercing weapons such as spears primarily or perhaps an estoc would go through chain by seperating the links pretty easily. Bludgeoning and picks against heavy armor. Many a knight dropped his sword and pulled an axe off his horse when he went on foot against other knights as well since his sword wouldn't work very well.
You'll have to consider a few weapons individually also. For instance the Rapier. Listed as a medium weapon due to it's length, but it's finesable and does only 1-6 points of damage. Realistically a dagger would penetrate heavy armor better than it since a dagger has a broader, thicker base and a short blade to hold up to striking heavy armor. The long, thin blade of a rapier would snap, or deflect pretty easily. Therefore, I gave the rapier a -1 to heavy armor even though it's category is a Medium Thrust Piercing Weapon.
Rapier 20 1d6 1/1/-1 18x2 3 P
Many double weapons although considered large due to the fact you need both hands to wield them are not wielded like a traditional two handed weapon and should be placed on the medium category for these purposes.
Quarterstaff 1d6 0/0/0 20x2 4 B
Armor AC Max Check Arcane
Category Bonus Dex Pen Fail. Spd.
Light
Padded 1 8 0 5% 30/20
Leather 2 6 0 10% 30/20
Lt Hide 2 4 -2 20% 30/20
St Leather 3 5 -1 15% 30/20
Courbouilli3 5 -1 15% 30/20
Lt Scale 3 4 -2 20% 30/20
Chain Sh. 4 4 -2 20% 30/20
Medium
Hide 3 3 -4 20% 20/15
H. Courboulli4 3 -3 20% 20/15
Scale Mail 4 3 -4 20% 20/15
Brigandine5 3 -3 30% 20/15
Lamellar 5 3 -4 30% 20/15
Chainmail 6 2 -5 30% 20/15
Breastplate 6 3 -4 25% 20/15
Heavy
Splint Mail 7 0 -7 40% 20/15
Banded Mail 7 1 -6 35% 20/15
Half Plate 8 0 -7 40% 20/15
Full Plate 9 1 -6 35% 20/15
I have weight and cost also of course, but didn't fit. These are my 3 categories for light medium and heavy armor in regards to encumburance, but with my system with the weapons Light is amror protection of 1-3, medium is 4-6 and heavy is 7+. This puts hide in with the other leather armors for that purpose and chain shirt in with the mediums. This also means natural armor gets a category as well. If some thing has both natural armor and is wearing armor add them together.
In a damgae reduction system I would split the AC in half with the 1st number being deflection and the second one soak.
Like wise with my weapon modifications I would then say the first modifier (whether positive or negative) would be vs the "to hit" roll and the second would be against the soak. Examples:
A two handed Mattack would be a +2 to hit and would ignore 1 point of DR from Heavy armor.
A Halfling fist vs heavy armor would be a -2 to hit and would actualy add one to the DR. EeeeK!
Just an idea.