Soliloquy, The final RDM job ability.

[Limar]

Yeah but why even bother with the spell cast? What I want is a job ability that opens the mob up directly for a MB. If I want to cast spells, I want them to count. I'm an Elvaan. Unless I'm in Aby my MP pool is finite. I don't want to spend levels 91-99 in aby.

You want to spare some MP outside of Abyssea? Open your SC with a T1-Spell. All you want is the SC. Either Don't MB, MB with an enfeeble or switch staff in after you WSed for more Nuke DMG.
You are in Abyssea? Get a higher tier spell for some added Dmg. You can even cast in Full Nuke Gear Except Weapon, Ammo and Ranged-Slot.
Can't see the problem here.