@Ixal No I'm right. Get your nose out of Europe's butt. Speed is only relative to your opponent. As much as Europe likes you to believe, you are not a walking invincible fortress. Plate armor has weaknesses. The joints and heat exhaustion. By the time the simpletons of those days realized this and tried to fix it guns were in production. The reason joints were a weakness was so you could actually have a range of motion. You could not protect those spots. You literally had to struggle to protect your armpits, the back of your knees, the tendons on your arm near your bicep, etc.
Please learn your history. Yes, joints were a weak point of plate armor, relative to the rest. They were still protected by mail, sometimes even plate, making them impervious to swords. You would have better luck with a dagger. A less armored combatant would have 0 advantages over someone in plate because 1. plate armor is not slow, especially comapred to other forms of armor and 2. it provides a gigantic advantage over people with lesser armor or even no armor (= suicide). The idea how the agile master swashbuckler having an advantage over combatants in plate armor is a hollywood myth (Syrio Forel from GoT for example). The same way it is a myth that plate armor meant you couldn't be agile what you seem to believe. See the videos, and no those are not aluminium replicas but real plate armor.
Plate armor was bulletproof by the way for quite a long time and it took more than a century of firearm development until plate armor could not keep up any more.
