Ahri A Kiting Mage, I think Not
Look, nobody can really deny that these new changes to Ahri have been pretty decent. In fact, It has helped her winrate if you want to use it as a metric of her strength.
The issue right now is it is almost impossible for Riot to continue to increase Ahri's mana costs, and call her a Kite mage. At level 2 a Q+E will cost Ahri 1/3 of her mana pool. Not only is Ahri's mana pool incredibly low, but her mana costs are increasingly higher and higher. Unlike Lissandra, who has an incredibly short CD Q, and a way to help her mana costs in the form of a crappy passive.
Ahri's CD's, while not short, are long enough that the fantasy of a kiting mage is not as easily created. Additionally, when your only non-ultimate kiting moves cost in the ballpark of 100 mana each late game, with a mana pool of only 1184 base at 18, there is no way to argue that she is a legitimate kiting mage in her current iteration, and nerfs to her mana costs are not the right way to go.
If you think she is strong Riot, OK that's fine. Don't hit her mana costs, because they're already oppressively massive as it stands.