Most of the core issues that SCH has in terms of gameplay are not being addressed with Endwalker. While fairies may or may not be more responsive (TBD), there is a ton of inherent clunk still in their design. It really makes it hard to be excited for the job in Endwalker.
The job still regularly locks itself out of its own abilities. Dissipation still locks you out of Whispering Dawn, Fey Illumination, Summon Seraph/Consolation, Fey Union, and Fey Blessing. Seraph still locks you out of Fey Blessing and Fey Union as well. This is extremely disheartening.Why do they feel the need to perpetually have this job's kit contradict itself?
Energy Drain still exists. The problem with the initial 5.0 SCH release was that you'd have excess stacks when Aetherflow came back up. You couldn't just throw out random Aetherflow heals, because that would come at the cost of being forced to use Ruin II, which was a damage loss. If SCH had a 1.5s Broil back then, it wouldn't have been as severe of a problem, because you could use essentially free Sacreds or Lustrate/Excog to burn the excess with no damage loss. Sage actually has this design, where they are actively rewarded for using their Gall heals with MP return.
Keeping Energy Drain actively makes SCH in Endwalker NOT want to heal. In fact, Energy Drain is effectively buffed by a 1.5s cast time, as every use of Energy Drain is now a 100 potency gain. Previously, you'd have to weave some Energy Drains on a Ruin II, making the effective potency gain only 10 (290 Broil Vs 200 Ruin II+Energy Drain). This makes Dissipation even stronger, and even more important to be used as a damage tool, which makes the kit feel even clunkier, as you get forced into those awkward situations to do your best damage.
One of the things that makes SCH also feel clunky is that you only have 3 buttons that benefit from buffs that "Increase healing magic potency", but you have two buffs that do just that within your kit. So, the only things in your kit that benefit from Dissipation or Fey Illumination are Physick, Adlo, and Succor. Embrace and Seraphic Veil also benefit from Fey Illumination. Not only does SCH have few buttons that benefit from these, but its GCD heals are also weak compared to what the other jobs have. These won't apply to your primary healing tools, your Sacred Soils, Indom, Whispering Dawn, etc.