Regarding armor i always liked damage reduction. If we look at this realistically, wearing heavier armor would make you easier to hit but harder to wound. That was one thing that always annoyed me in D&D...i still fondly remeber the Thac0.
Not sure if thats implementable in 5e.
It's also effectively damage reduction in D&D. You wear heavier armor > you take less damage. But mechanically, instead of absorbing X amount, armor absorbs all or nothing.
It's more abstract, just like the whole concept of HP, but mechanically you still know when armor "does it's thing". Hence it should be presented correctly in a video game instead of only using dodge animations for misses.
