The Skyrim formula is a very poor choice of design.

The Morrowind formula (without the whole dice-based dodging) is better, but not a whole lot better.

The Mod I linked has the better formula of the 3. It is simple to calculate, benefits are linear and does not need to be artificially capped.

Unfortunately, a comprehensive mod would be needed that also re-balances the game across all levels accordingly, not simply the armor formula.

The damage reduction formula skyrim (and oblivion) uses was likely made in response to criticism that, in morrowind, ebony armor made you inmortal against everything except vivec.
With damage reduction in percentage (and capped) enemies always get to inflict some damage, keeping the game challenging. Unfortunately that system has his flaws too. for example; increasing your armor by 100 points now make little difference and even at maxed armor you take considerable damage from strong enemies.
This makes HP more useful than armor (when not abusing the enchant loop trick) and seems to be the reason why the developers decided to give most enemies little armor rating. This, in turn, makes destruction spells less useful since their ability to ignore armor is irelevant.
I agree than a system like fallout (which uses the two formulas) would have been better.

Very well said.

+1000

Nope, giants barely make a dint on your armor when you hit the armor cap.