My main gripe with Dissipation is that it's simply outdated.
It's actually fairly good in UwU, you GCD heal more often and 20% on those is good. The additional AF is also good since you use AF heals far more often. Losing your fairy for 30s is not as big of a loss as currently since you only have Whispering Dawn on 60s and Fey Illumination on 120s and Aetherpact. No Fey Blessing, no Seraph, no Recit for free crit Indoms, more limited toolkit in general.
Which makes it easy enough to use to take full advantage of everything without any downsides whatsoever.
But several expansions later, 30s lockout turns into a major problem because we have 2 more fairy skills, we barely if ever GCD heal, we even trim down AF heals to the bare minimum or even full ED spam.
Spreadlo is usually a waste of GCDs outside of transitions when you don't have a target anyway, so no point in megabuffing a shield when you can just press Whispering Dawn afterwards.
There's also the problem that it resets your fairy placement which is a major pain in the butt.
So if they lowered the lockout, let it affect oGCDs as well, let any AF spent count for the gauge and simply made the fairy phase out at its spot so you can't use fairy skills but stays in place, I'd be fine with it. I'm not opposed to being taxed in some way, SCH is the last healer that has to think a bit more when to use heals instead of just churning out free heals all day so I'd prefer it to stay that way. Besides, it's still ahead in dps even with the taxt so it's not like it doesn't have a spot because of this tax.
But if they could rework it to something more interesting like resetting/ lowering other fairy skill cooldowns or make it more flexible with a lower cooldown and adjusted stats, I'd be all for it. As long as it's a button you have to think about carefully when to use it because it could backfire if used poorly and not just another "just press it lol" button that makes HP bars move to the right. We have enough of those. I like Roe's idea of dividing all stats by 3, more flexible cooldowns suit the newer encounter design better in general.
And for god's sake, just make the fairy reappear after death already instead of us having to waste another GCD before we can even nom nom nom it for AFs.