Oooh, I got a small idea...
Job Ability
Soul Aura
Grants the Buffs on RDM to players within Area of Effect. Overwrites existing buffs. RDM loses said buffs.
Recast:2minutes
Duration: Instant
Every job can Accession as /SCH, So this isn't as broken as you might think, Plus it could be level 91+. Plus the RDM loses the buffs (having to recast them). If RDM is truly suppose to turn "Mere mortals into demi-gods" they need a strong boost to buffing potential, This would give rhyme and reason to single-target buffs RDM has.
This will also help RDMs buff parties by buffing themselves, then using the JA, everyone in range gets their buffs, but they lose their own! There could be another draw back to it, to "balance" it. But Im not creative enough to think of a good one.
It could also Spread the love of "Composure" buff durations, to the point it would even help some other mages (Due to added duration).
WHM would still have stronger potency buffs when it comes to Pro/Shell, and Barspells, but RDM being able to buff themselves then AoE it by removing it from themselves saves time and will help RDMs workload a lot. Leaving room to cure!