I'm not against variety at all, yet I think the categories that suffice for armour (and their sub-types) would be Heavy, Light and Unarmored. I can understand these three ways of considering armour in one's build, but I fail to see how much value Medium would add in terms of fighting philosophy (so, pls, I am not here to bash at those who favor it, just trying to understand why).
Heavy is pretty clear, you're gonna take loads of hits in heavy metal situations and want to absorb most if not all of it.
Light means that you wanna take a more careful approach to situations with potential confrontational outcomes, but be ready to have some protection if caught unprepared or if, well, all hell breaks loose.
Unramored means you will rely on the efficiency that your attacks will cause so that you do not have to face direct combat, but that in emergencies you are able to make the best of your natural Agility and Speed to protect you somehow.