Addersting just needs to be reworked.

As it stands, it's not satisfying in any conceivable way and is an aggressively convoluted way of getting a highly limited amount of ARR/HW Ruin II. Because that's what it is. Ruin II used to be the same potency as your Ruin or Broil and just costed more MP. You had the freedom to use it as needed without losing DPS without feeling obligated to spam it. I have no idea why it was ruined, but that's healer design for you.

Toxikon should not be that, but there are several issues that we run into trying to create an easy solution to the problem. To address your suggestions, you cannot have Toxikon be truly DPS neutral when you can generate it both on and off the GCD. If we boosted it to 660 potency, it would be DPS neutral with E. Diagnosis, but a 330 potency gain to use Rhizomata on cooldown, and you'd want to save your Addersgall for burst windows, ignoring their healing value in some cases because that would help you push out numbers.

Leaving Toxikon on the GCD and leaving methods to generate it on the GCD has the potential to make SGE gameplay more fun and diverse because that helps take you away from Dosis spam which is what all of us want to see from all the healers, but it needs to be obtainable in ways that makes it DPS neutral or a gain, but we also can't just buff the potency because then SGE spams E. Diagnosis instead of Dosis in most occasions, because you get the same amount of damage and healing/shielding for only 100 more MP.

Making E. Diagnosis not a total joke of an ability and allowing it to break up Dosis spam through Toxikon is a great idea, but it needs to work without invalidating Toxikon either, essentially.