I am an avid Ahri player, and I have always loved the ability to default on a Moonflare Spellblade when my enemy used a lot of CC. However, now with Moonflare's removal from the game, where is Ahri, and other AP Glass Cannons like her, going to get the Tenacity required of them while still getting enough magic pen to be effective? Sure, many people hit Moonflare as only giving 40 AP and Tenacity, but it has saved my life in matches with Ashe and Teemo. Now, without the tenacity boost, the only way to mid appropriately against something like a Morgana for many AP carries would be to buy something that does not supply AP. Why? Moonflare is out, and no item that provides Tenacity and an AP boost is back in. Ahri, Katarina, and pretty much any other squishy AP character will either end up destroyed by other AP carries, or have to make some kind of weird item set using mana boosts and an Archangel staff. Either that or go Boots of Mercury treads and have to buy a Voidstaff/Abyssal Scepter. It was just a lot simpler and easier to build Moonflair as a special conditioning item.