Druids of the flame are stupid. Nowhere in their lore do they interact with fire. And we're supposed to believe that lighting a cat on fire gives them super powers?
No. If they were corrupted by Deathwing they would be using the opposite of their nature magic which would be plague magic. They'd cast diseases and poisons not fireballs.
All of this is especially bad because there's another class in this story line that DOES have a history with fire: shamans. If shamans were corrupted it makes sense that they'd turn to flame and begin to worship Ragnaros.
IMO the new form this patch should have gone to shamans. Their ghost wolf form should have been a fire form. Or their Feral Spirit should have been given the fire form.
This flaming kitty nonsense needs to never happen again. It reeks of a story written by the art department.