In many of the high-end fights, we have many situation where each healer heals their own respective portion of the damage and have to heal separate objective such as ST/OT. I have already seen parties that deny SGE by locking the spot to SCH.
IMO the bare minimum adjustment for Sage healing is the following:
  • Diagnosis to 700 potency without changing E. Diagnosis: this is to quickly bring up hp of the revived party member. I had many situations where I have nothing but E. diagnosis because my addersgall is for the next incoming party aoe/tank buster. I have to pray that the downed is healed by co-healer. No boss is really gonna wait for me to cast multiple cure 1. (WHM/AST/SCH laughing with their fat heal) Hell, I sometimes couldn't even save myself after I get revived. It is just stressful.

  • Rhizomata to 60s cooldown: addersgall feels harder to preserve even though it charges up after some time. SCH aetherflow is 3 stacks right away per 60s for multiple uses.

  • Holos and Panhaima to 90s: this would make boss heavy constant damage situation much more manageable without taxing the co-healer.

  • Haima to 60s at least: Consider SCH Exocogitation is 45s. Haima on the other hand with similar usage is a harsh 120s for no reason. I hated the idea that I must save Haima for tank buster and no other use when SCH can throw Excog on revived party member as well as constantly throws it at the tank on ANY situation.