Just a few ideas I had that I thought I'd put out here.

New spell:

Contagion: When target dies, enfeebling magic effects on target are transferred to all targets in a small area.

This spell would exclude Dia and Bio as well as songs, JA and WS debuffs, and Elemental and Dark magic debuffs. Basically limited to what RDM can cast normally minus dia and bio so as to no unintentionally spread dot damage. Timers would carry over.

Changes to Enspell IIs

Make functionally the same as Enspell 1s with the following exceptions: Can be cast on other players (as how Phalanx II is) and provides a modest buff to a stat based on element. Enfire II would grant attack+, Enthunder II Accuracy+, Enwater II Magic Accuracy+, Enblizzard II Magic Attack+, Enaero II Evasion+, and Enstone II Defense+. Buffs would be modest but not worthless, perhaps scaling up to +50 based on enhancing magic skill.

New Job ability:

Concentration: Increases Magic Accuracy and Magic Attack bonus, Reduces MP cost of Elemental and Healing magic spells, Reduces Physical attack speed. Increases effect of Enhancing magic spells cast on others. Overwrites and is overwritten by Composure. 5 minute recast

Alternate stance to composure for back line capability. Stat bonuses would be modest, +30 or so, -10~20% MP cost reduction. Physical attack speed would be a potent Slow effect (not weapon delay) -30% or so. Enhancing magic would be a flat x2 multiplier to all spells cast on other players who are not RDM main (trying to avoid situations where one RDM on Concentration buffs a second RDM on Composure, potential for enspell abuse there...). This would apply to all enhancing magic spells, not just ones that scale with skill (Haste II for example). This JA combined with the changes to Enspell IIs could potentially allow a back line RDM to almost fill the role of a BRD in some situations while not overpowering it in other areas (able to cap magic haste on other players as well as a decent attack bonus via Enfire II and accuracy bonus via Distract, still not as potent as BRD but maybe at least a viable alternative, it would be really nice if BRD and GEO weren't required jobs for every party...)