Besides Aero, there's one thing a lot of WHMs seem to forget about (minus the annoying ones who use it on mobs): Fluid Aura. No MP, no cast time, no knockback if it's used on a boss, and it's off-GCD so the only risk is getting close to the boss, and there aren't many bosses I can think of where it's dangerous to do so. 150 potency every 30 seconds is fairly negligible but free damage is free damage, especially if you can pull off Cleric Stance beforehand.