Burst Effect: Light RST to all allies (honestly, I just copied this idea from AW Sol because her burst effect gives Dark RST to all allies, so why not the opposite on AW Osiris? Though I actually don't know how much % AW Sol gives, cuz I can't find it in the jp wiki)
Shoot Mirage++ = All I can think of is adding a Dispel to this move to justify its long cooldown
Sekhet Ial++ = my first thoughts for this was turning it into a teamwide Nullify but... that would be pretty OP and broken, so perhaps add something like guard all allies to this ability for 1 or 2 turns (would compliment her self nullify very well), or something like a taunt perhaps? or maybe add a 2T 30% or 40% damage cut to all allies instead
Dark Harvest+ = obviously, increase the heals to something like 1800 or 2000, then the burst gauge increase to 20 or 25 (I want 30 but again, that's just me making her more OP lol) and maybe have Cleanse as well so she can match up to Sol
Passive ability:
Def 8% (probably just like Hades awakened, unless they increase this even further)