Coredump said:
No question, the knight is more of a danger. I would easily pick the ranger as my opponent. Especially if the knight gets a shield also....
The reason heavy armour went away was NOT because of dexterity, that was not a 'new' thing. The advent of gunpowder is what killed the usefulness of heavy armor.
.
Actually, I believe you are quite wrong...
I'll have to drift completely off-topic here, but in short the advent of the crossbow completely killed off the night.
Prior to that, the art of fencing was rapidly making grounds against the armored fighter, which is what we are talking about in a DND reference.
Knights in heavy armor were heavy cavalry, not infantry. The reason being no one could hike 20 miles in 120 lb armor, carrying a 20 lb sword. They were the shock troops - typically used to shatter enemy formations. The Men-at-Arms on the ground, usually dressed in leather and/or chain-mail, depending on the wealth of their liege, would then close in in formation, often backed by archers (or british longbowmen)
An armored knight on foot facing even as few as three determined peasants was mincemeat - though most flatly denied it. Quite simply, the broadsword of a knight was fearsome, but left them viciously open to multi-attacks. Their slow movements and 'broad' style of fighting left them particularly vulnerable to lightly armored, rapier/epee wielding opponents.
There are some accounts of duels between armored knights of the previous generation and the younger dandies... the dandies almost invariably won and often mocked their slower moving counterparts
Crossbows put the heavy knight into a coffin, and gunpowder sealed their fate, but the dandies were the ones to start the process.