From the pages of Black Pudding #6, here is a house rule about armor class.
Prowess AC is an idea that I think would serve any sword and sorcery campaign well. If you're doing a high magic game, probably not so much. I'd also strongly encourage allowing PCs to improve their ability scores over time and/or having a more generous stat generation method than 3d6.
For those who might complain that this is unrealistic because of real world combat, all I can say is keep doing you and I'll keep doing me. Peace out.
But seriously, feedback is always appreciated on these little house rules as I don't always have the opportunity to test them out.