Developers : Healer design mentality needs to change

[Absurdity]

Seraph is another possibility. I am ok with Lily being strictly support, but Seraph should really change things while she is out. This is (should be) SCH's burst window, so at the very least, Seraph should grant potency increases to all of SCH's actions, including Broil and Biolysis. Again, this would give Seraph usefulness in dungeons as she will not only grant sustainability to the tank, but she also helps the SCH kills things faster.

Since we're on the topic of Seraph you could also change Seraph's toolkit depending on which fairy you had before summoning her, healing oriented when summoning Seraph while Eos is out and dps oriented when you had Selene instead.
Since Consolation is currently the only useful shield I wouldn't want to change Seraph to a dps only summon entirely.

And now look at that. Two simple changes and SCH becomes hella fun to play again in both dungeons and raids, and it is done in a way that makes the 'heal as little as possible' mindset SE is frowns on redundant because there is no reason to hold onto DT to fit into Seraph's burst window since it is effective without increasing SCH's ST DPS. However, the moment you make DT something that does increase damage, then it changes everything, and the devs know this. The same can be said for Excog by giving SCH the option to use it for damage. This is how the illusion of choice is created and must be avoided at all costs when it comes to the healers.

I don't see much of an issue with DT becoming an aoe dps tool as that would really only affect dungeons and it already rarely matters in that content.

[Gemina]

Since we're on the topic of Seraph you could also change Seraph's toolkit depending on which fairy you had before summoning her, healing oriented when summoning Seraph while Eos is out and dps oriented when you had Selene instead.
Since Consolation is currently the only useful shield I wouldn't want to change Seraph to a dps only summon entirely.

Unfortunately, that just creates the illusion of choice as the optimizing SCH will always be sure Selene is out before summoning Seraph, so half of her toolkit will remain underutilized due to only being useful in niche situations. That is what Seraph basically is now, so this wouldn't change much about her.

I don't see much of an issue with DT becoming an aoe dps tool as that would really only affect dungeons and it already rarely matters in that content.

It's not an issue so long as it doesn't boost the SCH's damage in an ST scenario. In the case of spreading Biolysis to multiple targets, this is an exception because it doesn't matter if it is used inside or outside Seraph's window. However, if DT could for example thundercloud a Biolysis for full damage plus the DoT, then it will unquestionably be used inside of Seraph's window if Seraph being out boosted the SCH's damage, effectively reducing your options of when to use it to just one. You would never see SCH DT an Adlo ever again unless its CD is at least half the duration of Seraph's, but as of right now since these CD are both 120s, the former would indeed be the case.