Sling damage versus Large creature. Particularly how sling damage increases versus large damage and how he finds issues with that idea.
Which leads to a wider question of the consequences of the different options for modelling weapons, injury, and armor class in various editions of classic DnD.
In Chainmail man to man combat the odds of an opponent be killed was found on a chart cross indexing weapon versus a specific type of armor. You roll that number or higher on 2d6 and the target was killed.
This element was not in the original release of the 3 LBB (Little Brown Books) but worked it way in with the release of Greyhawk. There it was presented as a weapon versus AC chart. Using the chart would result in a modifier (or not) to your to-hit roll if you were using that weapon versus that armor.
The chart is derived from the man to man chart in Chainmail. Basically that was a 8 or better to hit was a +0 modifer and the rest were calculated from there. Although Gygax tweaked the number as it doesn't quite line up with the man-to-man chart.
Greyhawk also saw the introduction of variable weapon damage where each weapon used a different dice and/or modifier. Along with a different set of damage for large creatures.
Finally in ADnD we see weapon length, weapon space requirement, and weapon speed factors. Weapon length explicitly defined how far an opponent can be attacked, and weapon space defines how small of a space a weapon can be used effectively. Weapon Speed factors only came into play if initiative was tied and could result in multiple attack for the wielder of the weapon.
The State of the Mechanics
Not all of these mechanics found their way into people's campaigns. Either back then or today. Of these varying weapon damage is the one that is most commonly used. A different set of damage versus large creatures is not found as often. Weapon Length is sometimes a factor especially if the weapon is clearly a polearm meant to be used in the 2nd rank or further back. Weapon space requirements is also run on an ad-hoc basis.
Weapon versus AC may be a little less popular than Weapon Speed Factor but not by much. Both are are generally not used. Weapon vs AC involves yet another chart lookup, and Weapon Speed Factor was part of a initiative system so poorly understood that there are two separate interpretations and multiple page documents to attempt to explain them.
So when it comes to my Majestic Fantasy Rules, my reasoning was a follows. The core of combat is the to hit roll versus Armor Class. It bundles actual contact with overcoming the armor into a single roll and an essential part of how classic editions work.
I think varying weapon damage is the way to go. Injury is caused by force. Force is determined by mass time acceleration. Different weapons have different masses and are designed differently to channel that mass into force. So varying the damage dice for different weapon is a good way to model this without getting overly complex.
Because damage is a result of force, which equal mass time acceleration, it doesn't make sense to me to vary damage for large creature. Instead a more straight forward method to give them more hit point or hit dice to represent their increased mass. Luckily classic DnD is consistent with this with the various giant versions of creatures so I don't have to do any work in this regard.
As for weapon speed I prefer individual initiative where everybody rolls 1d6 plus bonuses. High roll has the option of acting first. The classic weapon speed mechanic has little relevance for me as it tied tightly to the ADnD initiative system.
While I think that Weapons versus AC is one chart too many, I think the concept is sound. Different weapons are designed differently and some are more effective than other against certain types of armor. Despite the abstract nature of classic edition combat, it at level that I think a light touch would be add something to combat.
I opted to handle this by noting any special bonuses in the description of the weapon. For example maces gets +1 to hit versus opponents wearing chainmail or gelatinous creatures like ochre jellies or black puddings.
This method allowed to add other interesting attributes to weapons with a similar light touch. For example an axe can be used to pin a weapon if the opponent fails their saving throw. Something I learned from reading how axe were used throughout history. Typically this is followed up by a blow from the shield or a takedown after grappling with the opponent.
You can read my take with the either of the following two free downloads.
The Majestic Fantasy Basic Rules
The Majestic Fantasy Equipment Rules