From Chainmail to D&D Next
Chainmail has historical significance as the step between war gaming and D&D Alternative rules. It allows any kind of mid-evil or fantasy combat to be played out on a terrain table with miniatures.
My favorite part of the rules is the ease of going between skirmish and man-to-man combat. This makes it easy to play out a combat where the heroes are smashing through hoards of Orcs, and then switch into man-to-man when the leader comes forward to engage the hero in single combat.
The rules are hard to read and understand without a wargaming background. The alternative D&D rules are simple and work good for man-to-man combat. These and other short coming have resigned the Chainmail rules to history. But I wished that instead of adding variable weapon damage, Weapon Speed, and other complication to the D&D combat rules they would of kept more of the chainmail rule feel.