All these nerfs to AP Yi screws over the people who want to play him as AD or even Jungle. What's the point of nerfing his Meditate when a team comp in any ranked or normal play that has no CC gets punished because of not getting any hard CC's.
Additionally, Morellonomicon and Executioner's Calling allow him to be finished during his Meditate. If you don't shut him down in lane, he becomes a problem. But you can say the same for Vayne, Kog'Maw, Pantheon, Kassadin, Nidalee, Shaco, Akali, Shen, Dr. Mundo, Caitlyn, Ashe, Morgana, Brand, Malzahar, etc.
Should they all get nerfed because they are unstoppable when fed enough?