I have to say, seeing Aegislash at #1 is something I actually expected, and I assume that it'll still be really high in the stats in future months. If there's one new Pokemon that I've always thought would have a shot at being the next "King of OU," it's Aegislash. Even with Steel's Dark and Ghost resistances removed, Ghost/Steel is still a great typing. Sometimes it seems like Aegislash has a 720 BST since it always attacks with 150/150 offenses, always switches in with 150/150 defenses, and smart playing with King's Shield will ensure that it continues to take hits with that same bulk. Swords Dance and Autotomize are both great boosting moves for it, the mixed set is really cool and pretty hard to switch into, and bulkier sets with King's Shield make great bulky pivots. It's probably my favorite XY Pokemon to use right now besides maybe Talonflame.