EsXcape, have them look at their tp allocation again.
Druid's have a skill called Pure Healing which is their passive healing mastery, and Priests have the same thing, called Faith.
These work similar to a Mage's elemental masteries (which is why some mages thought they were nerfed, they forgot to put points in them or in Wisdom, mage's Intel boosting skill).
Pure Healing and Faith both max out at 50, and I'd be willing to bet your nerfed healers just forgot what those skills do, since no one ever uses them- they just sit there passively. But they both have a massive effect on healing power, and forgetting about them will most definitely feel like a big ugly nerf.
Priests/scouts (probably all priests actually) need to remember to upgrade Prayer as well, which is the magical water damage mastery. A priest/scout in my guild was convinced Ice Blade was nerfed into the ground until he remembered that he'd forgotten to max that skill out also.
Hope that fixes the problem- let me know if it doesn't, ok?