I said "Adjust potency as needed" in my original post to clarify that there should be some numerical adjustments to ensure a healthy balance between each tool. Generally speaking, potency balance really is something that should be left to the designers to determine. One thing they have access to which I lack is the ability to prototype changes. Let's say we find that all that extra mobility does make Sage a lot easier to optimize cast times with and that, as a result, does mean that Sage has too much power. Then it's a simple solution of properly adjusting the numbers, which is something expected of a game designer. And we can also address that balance in the other actions as well, not just in Dosis' potency. Maybe Phlegma goes back to being 510 potency, for example instead of 600. The point of my post is to establish a play style that does not exist in FFXIV that I want to have, and I want it to be balanced with the other healers. I don't want it to be OP, I just want to have faster, more active DPS gameplay while I heal, and have to balance those choices with my healing. Mobility isn't nothing, but it isn't everything either. You can absolutely have a more balanced relationship with the other healers even with this set. It's just a numbers game.
At the end of the day, I'm tired of being treated like I'm not allowed to enjoy that play style when it's something that used to exist in Scholar in the past, which is something I feel when I am constantly met with resistance to having even just 1 healer that plays this way.
One thing to note though is that only casting barriers to generate Toxikon usage is still a DPS loss. Because it takes 2 casts to both apply a barrier and cast Toxikon II. Two casts of Dosis III currently is 720 potency, whereas a barrier and Toxikon is only 360. With the changes made above, it's still a loss, but at least partially refunds some of the damage lost when you generate Addersting through barriers, which also makes Sage more forgiving in that sense to players who rely on GCD heals more often as clutch healing.