Fairy is a pretty OP typing. Instead of balancing the type chart, GF added a new type. Adding a new type wasn't going to hurt Dragons anyway because the problem with Dragons has always been that most Dragon types have high BST. The problem in Gen 5 (as well as weather wars) was the high amount of legends all typed Dragon and Outrage spam. Look at Druddigon. Its terrible. Now look at Hydreigon, Garchomp, Salamence, Zekrom, White Kyurem, Roaring Moon, Mega Rayquaza, etc. Fairy was a temporary solution to a problem that was bigger than the Dragon typing. If anything the Fairy type hurt Psychic types the most. It hurt Psychic because the one thing Psychic had it right was its supereffectiveness against Fighting. Fairy does everything Psychic does, but better. I think they're done adding types but a retconned type chart is something that I can support them doing. Maybe adding to the BST of more Fairy types too. A Fairy/Ground pseudo legend would wreck teams. Its probably a reason a mon doesnt have that type combo right now (or maybe ever).
More along the lines of ScarVio. I'm really hoping that they drop more DLC info. The new Terapagos baby in the anime is making me interested. A teensy weensy drop of info is all I'm asking but I'm afraid it will be like the ScarVio pre-release marketing all over again.