Personally, i think the most unusual/complex designs that arent able to normally win in a straight forward approach are the most enjoyable for me, since those add another layer of difficulty.
But overall, fun is subjective. On the matter of Healers, i think a great solution would be to carry over their PvP Job identity into PvE.
For Scholar i suggest:
-remove all regular Healing abilities and only give SCH Adlo,
a Melee range Channeled Heal that increases in potency over time(the one which you sometimes see in the MSQ during cutscenes when someone wounded gets healed from closeup),
Excog (providing a Shield) and Sacred Soil, thats it. The majority of its kit should manipulate said skills like emergency tactic turning any into AoE ( Protraction for example, turns into Sacred Soil).
For Dps Skills, remove Broil and Art of Dabbing and replace both with Dots of different magnitude and timer, return Bane (and make it upgrade into Bane 2 at some point which will also deal additional damage later on depending on DoTs on target), a Skill to make all DoTs "explode" on a single target for the full duration inmediately (long CD), a way to manipulate Sacred Soil into Shadowflare and rework Energydrain into a Channeled Ability where it weakens Enemies dmg, deals slowly increasing dmg and saps Mana.
The Fairies should be both Different from one another, where Eos supports healing abilities and Selense offensive ones (said Fairies CAN also be the trigger to change certain Skills as mentioned above).
Fairy controls should be changed in a way where they are placed like totems (like Liturgy of the Bell from WHM), BUT can also be placed on allies/enemies, where they Follow the target for the whole duration.
As for Seraph, imo it should be removed. It is just a nuisance in design and makes SCH look like a pseudo SMN from 5.0. Seraph is also never mentioned in SCH Lore and i think Eos and Selene should carry more weight instead.
On a sidenote, Inspiration for SCH can also be drawn from the Nu Mou, since they both have alot in common and fit themewise.