I am mulling the following approach armor.
I like armor being a proficiency, in the sense that learning how to use a shield effectively, and wearing a helmet along with bulky clothing takes some getting used to. But, I think it is ok for one armor proficiency to cover any and every armor. So, merge ‘light, medium, and heavy’ proficiencies into a single armor proficiency.
Instead.
I wonder if it is possible to think of armor as something that applies double the Strength bonus to AC.
So, a Wizard with average or worse Strength would get no benefit from any armor.
A person with Strength +1 would use an AC 2 shield effectively.
A person with Strength +2 would use an AC 14 scale armor effectively.
And so on.
A person with Strength +4 would use AC 18 plate armor effectively.
By contrast, a person with Strength +2 would only benefit partially if wearing plate, upto AC 14.
A person who is sufficiently strong would also suffer no reduced speed while wearing the armor.
Because effective use of armor requires a person to invest in Strength, it might be balanced if a Fighter who invests in both Str and Dex, to benefit from both the armor AC and the Dex AC. So a person with both Str +5 and Dex +5 would have a natural upper limit of AC 25.
Anyway, these are thoughts I am curious about. I havent made any decisions on it.
As an aside, the stealth disadvantage from armors make no sense. It is absurd that ‘padded armor’ (such as a gambeson) interferes with stealth, while a chain tunic doesnt. And in reallife, when wearing a chain tunic, one is supposed to wear the gambeson underneath it! Sometimes I wonder if the disadvantage from padded was a typo.