I wouldn't mind some additional interactivity, but to be clear -- I mean that as something which complicates decision-making in intended situations and offers more variety to button-presses, not merely something that makes a given function less responsive by requiring it to be bundled to/from a prior action or allows us to spam our filler keys even more.
I.e., a Dia that increases Glare damage would actually be worse, since now it reduces the use case even for skipping Dia in favor of Glare and therefore the benefit of correctly guessing enemy time-til-death. (Even a Dia with just more upfront damage would be preferable, as it increases the use cases for the less common action without simply holding the common action partly hostage to it and doesn't unnecessarily complicate one's average ppgcd to do so.

Likewise, something like old Bane, if it were put on a CD separate from any healing tools, would similarly reduces the number of non-filler actions one is enticed to cast during gathers or for AoE situations with fewer than 4 enemies. It's a seemingly cool function... but would actually mean you lose even more of the original variance. Whereas if Biolysis split its remaining duration among nearby enemies when its victim died and Bane were instead an Aetherflow action that added up all afflicted enemies' durations in the area, added some flat amount, and split them evenly across all mobs in that area, you'd at least be able to use it for burst AoE, offering new use cases for Biolysis instead of solely giving more AoW spam in situations where one could previously optimally DoT.
That said, interactivity from healer offensive actions whose use are limited by whatever means, be they hard CDs or soft CDs like DoTs or charged skills or what-have-you, often merely requires enough need for competing actions (e.g., GCD heals) that one's fight knowledge / awareness is rewarded through being able to fully leverage those more difficult-to-fully-leverage actions. That's been one of the foremost costs to making so much of our outgoing healing mere oGCDs, especially when there's no competing offensive value for those oGCDs' charges: Any challenge offense carries must comes purely from offense, since it and healing no longer interact or intersect in any meaningful way. And since we healers spend over 90% of our time DPSing, it would then take nearly some 90% of a DPS's kit to make that damage-dealing actually fulfilling.