I have concerns with your system and assumptions.
Azoth was just ONE of the aspects here. I dont think it costing 1,000 Azoth for ONE reroll would be cheap at all, especially combined with my suggestion of Repair KITS as well, which are 300 per kit. If it took even 10 repair kits, you are talking 3,000 repair parts to reroll ONE perk that would have like a 1-2% chance of hitting a desired perk…
Azoth TODAY is so cheap, because we dont have anything to spend it on. It was not long ago Azoth Vials were 100g a pop. So 1,000 azoth for 1 re-roll would run you 2k gold as well as the 10 repair kits which I could easily also see going for 100g+ a pop, so now 4k gold for 1 re-roll. Then factor in the % FAILURE chance, and the Daily/weekly COOLDOWN on doing this, it will in no way be “Too Easy to come by”.
As for UMBRAL Shards, the problem there is Umbral are not tradable. Literally right above your comment, Rochadura commented:
Your system forces crafters into PVE, especially at high mutation levels to get said umbral. I dont think we need to involve UMBRAL into this system. Using Umbral also doesnt address any of the other end game systems as I mentioned in this post.
My system involves repair kits, azoth, and Charms/Mods. It would massively improve the value of mods from chests, from the TONS of crappy gear we get, which we now NEED for the repair parts…
Your suggestion doesnt solve any of that, and just pushes people more and more into mutations as the only way of getting BIS.