Overreliance on cosmetics as a reward

[AmiableApkallu]

But outside of the relic grind, what other content rewards you with game mechanical advantages for taking the time to do said content? … … I'm just considering if maybe we should get some more gameplay mechanical too (empower or change a certain ability on your job for example)

This content already exists: class quests and job quests, and the "mechanical advantages" you get from them are generally regarded as a requirement or must-have, not an optional reward.