Horwath
Legend
agree.A lot of people have tried to come up with "better" armor rules and it's not easy. If you were to be realistic, leather and studded armor basically don't exist. Padded armor was the low end armor, made of several layers of fabric. The next step up (putting aside many, many alternatives) was chain armor. While quality varied, it was better at stopping piercing or slashing damage, but didn't do much for the concussive blows. That, and the weight distribution wasn't great because most of the weight was on your shoulders. That arrow may not pierce the chain armor, but it's still going to leave a bruise.
High quality plate armor on the other hand, was practically impervious to most blows. The scene in movies where someone stabs someone in the chest and it easily gets through the breastplate isn't at all realistic. It was even pretty effective against early firearms. But even in that high end armor concussive blows could still hurt, although unlike chain armor it could spread the force of the blow out. For the most part the way to kill someone in high quality plate was to wrestle them to the ground, pull of their helmet and stab them in the face. But that's not very exciting.
Which is my long winded way of saying, there's just not a good solution. If I were to change things I'd probably go with some sort of combination. Retain traditional AC indicating that the blow landing effectively then combine it with armor HP reflecting how well the armor is absorbing the impact. Of course you'd also want to throw in repairs and patches, especially to the lower end armors.
But it would take a lot of playtesting and some armors should be vastly more effective than others which isn't necessarily a good thing for the game. In other words, you're hardly the first person to go down this road and while I understand why people want to do it I just don't think there will ever be a great way to model armor for something as over-simplified as D&D.
while I would like some other mechanics of armor, current simply works good enough.
better AC, less chance to be hit, more effective HP.
only thing I would change is remove +X/+X from weapons to +Xd6 damage
and armor +X bonus to 2X damage reduction to all damage. Reduce rarity of +X armor by one category.