@Seerow: I assume you intend to use this along with a suggestion you made in another thread about having move speed penalties based solely on player Encumbrance, as opposed to having special rules inherent to medium/heavy armor?

Because that is the most blessedly simple armor fix I've seen yet. Obviously not all-inclusive of armor's problems but dear Lord. How did I miss that there are 2 systems in place to punish wearers-of-lots-of-gear to hit you twice with penalties?
Yes, if you check my Weapons, Upgrades, And More thread, I actually just updated the armor section to reflect that line of thinking.

That thread I'm keeping all of my changes to the gear itself, and core rules directly related to the gear. In this thread, I'm looking at a more radical change to the nature of Armor/AC in general. ie a baseline systemic change as opposed to a functionality change.

Right now I am working on a bigger write up for this, but I'm currently focusing on the fixing the RNG part as opposed to the temp HP part. I'm having a lot of trouble balancing it with Armor still providing an AC bonus, because you end up with hit rates akin to low levels (ie +4-5 vs 18 AC) across all levels, where ideally you want hit rates to be a little bit higher.

...actually, if I just shift it so that the baseline AC is 5 instead of 10, it should fit into place almost perfectly. That would get you a first level AC of 5+5(armor)+2(dex) = 12 vs +5 to hit. The hit bonus and AC both vary a little, but not more than a couple points in either direction. I think this could be a viable alternative to having to rewrite all armors specifically to accomodate a fixed rng.