I would like to see armor heirlooms nerfed a bit. No need to buff weapons, they are fine.
For proper body armors something like this should work fine.
+1: -0.2 weight, +1 armor
+2: -0.5 weight, +2 armor
+3: -1 weight, +3 armor
(listed values are combined, so it's +1 armor for each heirloom, for gauntlets, i would like to see also +1 armor per loom point, and total -0.2 weight, for helmets total -0.4 weight for fully loomed, for boots -0.3 for fully loomed gear).