I think we could come up with something better and simpler:
Notice that now heavy armor is always heavier than medium armor, and both always heavier than light armor. What a crazy idea, right?
Here is what armor types mean:
Light Armor: Made from supple and thin materials (usually leather or cloth), and maybe a few pieces of metal (just a helmet and or maybe protection for the right arm, etc.), light armor favors agile adventurers since it offers some protection without sacrificing mobility. If you wear light armor, you add your Dexterity modifier to the base number from your armor type to determine your Armor Class.
Medium Armor: Medium armor offers more protection than light armor, but it also impairs movement more. It is made with metal rings, scales or even plates (like a breastplate), but doesn't cover the entire body, although you will often use leather and cloth as padding or to protect exposed joints, etc. If you wear medium armor, you add your Dexterity modifier, to a maximum of +2, to the base number from your armor type to determine your Armor Class.
Heavy Armor: Of all the armor categories, heavy armor offers the best protection. These suits of armor cover the entire body in metal (of varying quality) and are designed to stop a wide range of attacks. Includes a helmet, gorget, or both. Only proficient warriors can manage their weight and bulk. Heavy armor doesn’t let you add your Dexterity modifier to your Armor Class, unless the modifier is negative.
What about stealth? Here is what I've got.
Some types of armor are noisy, usually due to heavy or low-quality material/craftsmanship. A creature has disadvantage on Dexterity (Stealth) checks while wearing noisy armor. You can find noisy, low quality light and medium armor for half the usual price. Alternatively, you can find good medium armor with additional pieces or layers that increases its AC by one, but also makes the armor noisy and doubles weight and price. Heavy armor is always noisy.
You could add a line about druids and how you can find nonmetal armor up to AC 12... but I'd go one step further and add bone, stone, etc., to give them even more options. But that's another subject.