I think giving WHM Solace/Misery would be a bit chaotic with the job already having a stance-swapping mechanic. If we're poaching from FFXI then I'd like to revisit things like Devotion (trade your HP for a party member's MP) or Martyr (trade your own HP to heal a party member in an emergency). Very, very situational, but interesting additions to the toolkit if balanced correctly. Or a short duration defensive buff of some kind with a long cooldown as a few suggested. It makes me sad that my other healer jobs can cheese some wipe mechanics but my WHM is purely reactive; I feel like I'm slacking when I throw down Asylum or cast Medica II and pray instead of having an actual party-wide defensive mechanic of some kind.

(And if we're poaching from WoW I'd like to have a heal like classic PoM, queued up in advance and jumping on use - it was just fun and even though it was mostly overhealing outside of PVP it was still satisfying to manage.)