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.

let that alone the cost to but Mercury's treads alone is almost as expensive as Sorcerer's boots and Moonflair combined.

Yeah, I realize I miscalculated on the merc's point. It happens in the heat of... I wouldn't quite say rage, more disgruntlement? Regardless, I see your point. I still find that it's not too interesting to me to have to acknowledge and predict which enemies will use CC late game from beginning game. I can do it, I just prefer having that safety point of knowing that the opposing team suddenly got a frozen hammer AND a Ryali's, so it's a good choice to buy moonflare. I see what you are saying, but I just feel as though I got shortsided when Moonflare was removed.

buying a void staff is a fantastic change to moonflair. Honestly i didn't like items like that they kind of stunk :/