You dont need looms to be good, so they are ok.It might be a big advantage for some to have a full +3 plate suit, but still you can beat them rather easily with cleverness etc.
What I find especially important to stay are the Gauntlets heirlooms, because they are the only possibilitie to wear your favorite armor and have decent Stats(If you prefer the look of lighter armors).
For example:
I use the ragged outfit a lot atm(23 body armor), together with my thick mail gauntlets(8 body armor), those gauntlets will have 13 body armor when they are masterworked, which will add in up to a total of 37 Body armor, meaning I get the Protection of a lamellar vest for a slightly higher price!But I think that fine because I like the Ragged outfit a lot.
So if you nerfed the armor heirlooms on Gauntlets especially, my Equipment would get considerably worse, thus giving me a big disadvantage just because I go style over effectiveness.