I'd think it'd be neat if they made Cure III consume Regens. The remaining heal leftover in regen then could be applied to Cure III's potency (Hopefully potency will be more than Cure II's). Make it single target and up it's cost and slap a CD onto it, because you could be healing for quite a bit with this mechanic. If not that then I'd be satisfied with a 7y-10y radius with MP cost of: 455mp.