The AP Xin Zhao changes.
The patch notes quote "Xin's exactly the kind of guy we want to see picking up Sated Devourer (more on this below!); or so we thought until someone stacked Ability Power with the Phantom Hit and managed to out-heal Dr. Mundo. Let that sink in."
He has always been able to out-heal a mundo.
Riot you claim to want diversity but when you see something like the AP option on Xin Zhao coming back to meta or near-meta status you shut it down.