For those of you who have forgotten, I'm an old school gamer who has become disenchanted with the mainstream rules. So, I developed my own and this is the way I deal with armor.

In medieval settings, the greater the stopping power (or soak) that the armor provides, the bulkier it is and the more it effects the character's movement and agility. So, sure! The characters can have that full plate, but they are taking penalties on number of attacks per round, distance they can move per round, and their ability to dodge or move about athletically.

In modern settings, technology makes it easier to create lighter armor with effective stopping power, so I make the higher stopping power armors more expensive to offset the benefits.

Armor has a structure that is broken down through absorbing damage. So all armor has its own version of hit points (structural points) and every time there's penetration, the armor sustains structural point damage and loses one stopping power rank. This means that the more damaged the armor, the less it can effectively stop, and the characters are then forced to spend their hard-earned dough on repairing armor.

In no system that I run does armor make it more difficult to actually hit a target. That makes no sense to me and never has.