Hmm Dunno. To me it's just same old same old. Regen, swiftcast medica2, dots/holy/dps. Use ogcd skills to avoid casting cures. Rince and repeat. I can simply last longer now that we have proper mana management.
The only tense moments I've had as whm is when the tank pulls those two pack right before the wave of bulldogs in Ala Mhigo, those brutes hit hard.
Ex trials with learning parties tend to be hardcore healing though. Once people get the 320 gear and get used to the fights it'll probably be easy.