I think people are taking this too seriously. I'm a huge lore nerd, but to my reasoning, these cards are developed by the Innkeeper. Yes, a dwarvish Innkeeper who created a card game in a sanctuary-zoned inn, using variations of existing heroes (and villains) of Warcraft. Basically, Hearthstone never takes a spin on WoW lore, the Innkeeper takes a spin on (his) real world events. :P
I hope he does say Live Insect! when he heals :P
To be honest, the lore was already wrong when came out. In WoW, moonkins are only found in cold forests and mountains.
My only problem is that Ragnaros and the other Elemental Lords aren't evil per se, or even corrupted. They were enslaved by the Old Gods, and Raggi and Al'Akir seemed to be willing servants. So simply "uncorrupting" him wouldn't be possible.But I could see him looking at , presumably a "Holy Fire elemental", and thinking: