[Note: My intention is to use Ascending Armor Class with Tactical Simulation Ruleset. For this post, I've used Descending AC to clarify the difference between AD&D weapon vs armor types and the method in Tactical Simulation Ruleset.]
Weapon vs Armor Class/Type modifiers are probably the most omitted section of AD&D rules. In my unscientific survey of fellow players and forum/blog discussion, most people liked the idea, but found the execution awkward or lacking. We also played a year or so of AD&D (more or less by the book), using the table with the same experience. Here are some of the common complaints:
1. The annoyance of referencing a table
2. The shield question
3. How to handle monsters
4. The modifiers are not realistic
I'm not going to touch #4. If anyone has a good source on weapon types versions mail, plate, etc, I'm happy to take a close look. For now I'll be sticking closely to the AD&D numbers.
The existing PHB tables takes up a whole page. That's largely a function of the variety of weapons, but it also makes for a wall of numbers. Character sheet layout with room for the modifiers can go along way. Let's take the next step by breaking the armors into types with similar construction. Padded armor isn't used enough to warrant it's own column. We could probably condense them further, but for now we have six types of armor and "no armor". To prevent confusion the armor types are indicated by a letter:
A: Plate armor
B: Splint armor, Banded Armor
C: Mail hauberk, Elfin (chain) Mail
D: Scale Armor, Lamellar Armor
E: Ring Armor, Studded Armor
F: Leather Armor, Hide Armor, Padded Armor
G: No armor
How to handle the shield? Ignore it. Perhaps this is the wrong answer for a pure simulation, but it throws the types off, adds additional calculation, and confuses players. Xerberon the Fighter is Armor Type 'C' whether or not he uses a shield with his chainmail. On the character sheet (ignoring dexterity modifiers) his player would note "AC: 4C" if he was using chain and shield, but "AC: 5C" if he was not.
Monsters: Gygax's suggestion in the Dungeon Master's Guide should be used across the board where the foes are not wearing actual armor. This will take some work, but TSR would be modifying some monster statistics already. I would probably do this off the cuff as I use monsters or plan encounters. The AC should be recorded similarly, so a Black Dragon might be "AC: 3A" and a Red Dragon "AC: -1A".
I'll post a review armor and shield list, the weapon vs armor table, as well as some sample monsters in a forthcoming post.