Disclaimer: As someone who has only played this game post ShB, I may not have the most accurate input when it comes to fixing this job as I am only going off of forum posts and wikis of its old kit.
To start off this list of ideas, I'm going to address the elephant in the room: One button DPS. To remedy this issue, I have a solution that could make SCH DPS more fun without over complicating its kit, as Yoshi-P is concerned about. Damage numbers will of course have to be changed, but for the sake of simplicity, I'm simply going to give a mechanical change.
First, delete Art ofBoreWar and give back Miasma II, Shadow Flare, and Bane. How a Scholar's damage rotation would work is much like how it used to be: Apply the two DoTs, bane them, then drop Shadow Flare. However Shadow Flare could be just a tad different:
Shadow Flare: Create an area on the ground that causes damage over time. Subsequent enemies also standing in the area along with the initial target of direct damage spells (Broil III, Ruin II, Energy Drain) will take a fraction of the damage depending on the amount of DoTs they (the subsequent targets) have:
75% less damage: No DoTs
50% less damage: One DoT
25% less damage: Both DoTs
Again, I'm not sure if this is already exactly how SCH used to play, but as a job that initially revolved around DoTs, I wanted a system that rewarded proper DoT management.
Second idea: To further help revive Scholar's identity, I was also pondering at the idea of deleting Succor while drastically reducing the cooldown of Deployment Tactics. This would involve strengthening Adlo shields on top of making the spell instant cast and having the barrier last for a shorter duration, all while reeling in all of the job's healing. A much simpler change but I figured this would encourage Scholar to use their GCDs more and truly make them feel like a tactical shield healer.
Third idea, and another elephant in the room: Selene. That one second silence she had I'm sure everyone knew was garbage, but I wondered at the possibility of giving her back cc in the form of an AoE slow that, at the very least, lasted longer than one second. Her second ability, which should definitely help her compete with Eos, would be an AoE damage debuff. She could still use Embrace as to still feel like a support pet. Not sure what her Fey Gauge abilities would be, though.
So those are just my thoughts on how to make Scholar feel more rewarding/fun without "over complicating" it. I'm happy to hear anyone else's thoughts as well.