It's a solid idea, nothing groundbreaking but it would give a solid cure boost to those who need it most, and without the ability to keep it on everyone at any given time it keeps people from prematurely trying to return RDM to WHM-1 again. Although I might go one step further and give the spell a ridiculously long recast time, or make it to where the buff can only be maintained on one party member at a time (per individual who casts it) just so it does not become another "cycle" spell.