Meanwhile dex based characters effectively never face this penalty. Because apparently having metal armor is somehow unbearable to sleep in but armor made from leather that's been hardened by boiling or having metal plates sewn riveted between layers of leather (aka studded leather) is perfectly fine. Or even if they don't sleep with armor, their AC drops the tiniest fraction.My 5e paladin goes from 19 in plate + shield to 9 in his skivvies. That's "good enough to make the dm's job harder" to "all combat is suicidal."
Personally? I blame the simplification of calculating bonuses. If the bonus to AC from dex was cut in half it wouldn't be so bad; but as it stands now plate armor gives you a whopping +1 to AC over someone with a high dex and studded leather armor.
Ah well. It's why I don't penalize people for wearing any type of armor in my game and never set up situations where people aren't in armor if they would normally have it.