I honestly prefer SCH to WHM. It is more complicated to heal a lot of dmg like WHM but it is possible while you are dps-ing on top of that. SCH doesn't have a lot of burst healing but it is the role with the highest oGCD healing party-wide and single target per minute. If only Energy Drain wasn't tied to consuming an aether stack. Then we wouldn't have been forced to choose between heal or dps in savage.
Dissipation and Energy drain should be revamped. But otherwise, I think sch is nice compared to whm.
Seraph locking you out from Fey Union is not a big deal. It heals the exact same amount distributed half in heal and half in shield. And usually, I think by the time you decide to use seraph, Fey Blessing would already be on CD. You want seraph because you need AoE healing and your ogcds are all used.
I personally would like it more if we had something like a personal seraph buff instead of Dissipation which augments our healing spells and abilities together with the fairy commands, the cure potency is higher while under the effect, and around half of it is applied as a shield. Something that is instant and reactive. Imagine smth like excog gets 800 shield potency upfront and 500 cure potency when hp drops below 50% while under the effect. Indom gets 400 shield potency and 600 cure potency, and Sacred Soil gets changed into Blessed Soil and converts x% of the cure potency of pure healing spells into a shield stacking up to 720 shield potency. Fey Blessing becomes Consolation while under the effect of the buff and Fey Union increases max hp of the target with each tick. WD applies the effect of rejuvenation which further increases WD regen timer by 5s-10s every time another fairy command is cast. Fey Illumination when executed under the seraph effect gives haste.
Emergency tactics is changed into transforming all shields cast by you into pure heals while under the effect.