Couple thoughts on Sage thus far:
1. The phrasing of Soteria and our attacks using "Kardion effects" definitely leaves open the possibility of having multiple Kardions out in the future. I'd love to see a cooldown to Kardion our entire team for a few GCDs, but that can be saved for a future expansion.
More immediately though, anyone else feel like Kardion's potencies are sort of... underutilized? Every attack is 170p healing through Kardion, but each spell has to specifically list that out. I'm a little surprised that, for instance, our AoE spells don't heal for any more than Dosis when dealing with a crowd (which is exactly the scenario you'd want that type of healing and make it actually competitive with Holy-spam, can't get much mileage out of Toxikon even if you can churn them out faster on pulls if you have to keep spamming heals), or Eukrasian Dosis doesn't effectively HoT the Kardion target (even as little as 10-20p/tick). Everything is just the same, no scaling.
2. I'm still on the fence about SCH's "critical Adloquium effects double the barrier" because it puts a huge portion of the protection you're meant to provide to chance, but at least Scholars have a cooldown to allow them to game that effect so they can guarantee such a heal when it counts. That SGE recycles the same mechanic with no such guarantee is bizarre, especially since Sage's barrier heal spells are weaker than Scholar's.
If this take on critical barriers persists, then I hope at least Sage gets the same diligence with regards to its own barriers in the future. For instance, if it could get sort of a "Enhanced Benefic"-esque trait from attacking (Phlegma?) with a low chance to guarantee your next Diagnosis/Prognosis is critical?
Granting I have the same opinion with regards to Freecure, that it should proc from attacks instead of lesser heals. Let the Green DPS do DPS.
3. The combinations of dual-effects on Sage's cooldowns are sometimes... bizarre. Not bad, just highly specific.
For instance, Taurochole and Holos each are potent instant heals with 10% mitigation. The burst heal suggests it should be used as aftercare, but the mitigation suggests it should be used to pre-empt an attack. There's the rare scenario where you use it to top someone off before a heavy attack that needs to be mitigated, but in all likelihood, the common usage will put at least one of the elements to waste due to the conflict between their timings, or at least reduce them to just one of the elements (ie overhealing with Taurochole in a rush to apply mitigation early in a pull, using Taurochole as just a stronger Druochole, or saving Holos for its healing after a raidwide has already gone out).
This could just be me being picky, I'm willing to defer to others on this one.
4. I agree with the concensus that Pepsis feels underwhelming as a single-target heal and response to Emergency Tactics (anyone know how it affects Differential Diagnosis?), but I would suggest an addition to its effect: If it removes at least one Eukrasian Diagnosis effect, it will return an Addersting. (Phrased like that, so it still only returns up to one Addersting regardless of how many Diagnosis effects it removes at once. No exploiting it by spreading Diagnoses throughout the party and bursting them all.)
This could hopefully kill two birds with one stone by allowing a Sage to cooperate with a Scholar healer, allowing them to generate Addersting (even at a reduced rate) with mitigated fear of having their effects overwritten.
Overall, I think Sage's healing model is unique and has a lot of potential to it, it just needs a little more meshing between its moving parts.