I admit I'm actually unsure why this ability has so much hate in terms of healing power?

Even if you just place it when a regular raidwide is coming up, it heals 400 on hit, then another 800 (4 stacks) a few seconds after. 1200-2000 potency raid healing on one button is incredibly good. Am I actually reading something wrong here or something, why is that underwhelming?

My only problem with Lilybell is that the cooldown is far too long and one decent toy doesn't fix the class. I'd rather it was less potency but a much shorter cooldown. But as an ability by itself, it's great.