How armor should work

Games these days treat armor quite differently from real life.

Citing an example, the armor value are usually translated into a percentage. It implicates that no matter how strong or weak the attack is, whether it is a cannon ball or a poke from the table knife, the damage being taken is reduced by half, even if the person is wearing plate armor.

Now that is ridiculous. Any normal human being would die from a direct cannon hit, and please do not tell me that a plate armor cannot completely negate a slash from a table knife.

Perhaps, the reasoning behind such mechanics is to keep armor consistent and useful from early game to end game, and although some games introduces a modification that improves the percentage against lower levels, I think this system removes common sense and intuition.

Instead, armor should have both fixed and percentage defense value. The fixed value would negate damage such as subtraction from inflicted damage. While the other value would work in the same way as before.

But the change is not just that simple. Every non-magically modified armor would only have that fixed value. So a chain mail is effective against a dagger, as a plate mail is effective against a short sword. However, a short sword would be effective against a chain mail, but not as much as a claymore.

The percentage defense value shall be treated as an add-on over armor as above, written as "Decrease Physical Harm - 2%". That means regardless of the incoming damage, it would be reduced by 2% due to the inherent magical properties.

This additional effect shall differentiate armor from its similar types, rather than from the current practice, where difference are only substantially noticeable when compared against another type. This is what I believe games should have, the mechanics where similar objects, can be vastly different.