[Lolzytripd]

Well the thing is, is that SAN and FAI are very specific to certain builds, they don't typically fit a melee fighter's role unless under certain circumstances, also not only to mention but old Tainted pertained to STR which was widely used in every physical fighter's build pre-GR, and while that hopefully persists today, some weapons don't benefit from a massive amount of STR as others do, causing a very large imbalance.

With that logic one should relate its effects to the weapon stats themselves and not any player stats, I'd hate for an enchant/curse to start becoming a stat buffer after all, I've actually wanted to propose a rework to Cursed effects in general, you never see Haunted/Parasitic/Tainted/Fleeting EVER be used in favor of rustic.

You could rework it into an offshoot of the Cursed enchant that monsters are frequently seen with, just have melee weapons inflict a random status from a list (not including stun, of course.) at the cost of some weapon stats, like accuracy/power/critical

Or give it scaled weapon power in return for the other weapon stats like accuracy/critical/weight

Hmm I think this a good train of thought.

Perhaps an unstableness to it where each turn it negatively affects one of the weapons attributes while giving a hefty buff to another.