What is the intended playstyle for immolation? The item gives you 150 defense and agility but completely neuters your healing ability, and I think these two stats roughly neutralize each other - every other shaman player will take regen or sac shrine, which heal at least 400 hp/sec (the equivalent of 1.2k ehp/sec). Immo, on the other hand, gives you about 20 seconds of healing as ehp up front, but you can no longer heal besides meleeing enemies for ~600 lifesteal every 2 seconds. What this means in practice is that you can't actually tank that much, because taking one hit with no recovery ability essentially puts you on death's door for the rest of the fight, and even with LS you're only going to be healing enough to stop chip damage from finishing you off.
Build-wise, you are literally locked out of all forms of healing besides LS (which is highly inconsistent in most scenarios), and the item has the highest combined SP cost out of any mythic. It is also nearly impossible to build with, since almost all FA items are tank items that give HPR (which is actively hurtful on this weapon) instead of meaningful damage stats. This means that the only "viable" immolation builds are extremely item-limited rainbow slap builds that must build tons of LS, or titano "big mac" (without hpr) builds where you are forced to ignore the air damage on the weapon, and even when building fully towards health sustain you still have no real ability to meaningfully recover after you take 1 big hit.
I think that immo's current base dps is not high enough to justify using the weapon. I don't think maxed defensive SP is so impactful (and so much more impactful than the crippling downside of neutering your recovery ability) that the weapon should also receive below average base DPS, and returning immo back to its previous 1020 base dps would at least allow it to deal higher damage (without needing to create more FA items to support it).

