It's not a buff, it's a reverting of a previous nerf. Irelia was just fine before, and fairly strong in the early game because of her ultimate's healing, making her laning power in the sustain and farm meta of past top lanes quite powerful and pushed her up too much, so they increased her rank 1 and 2 cd to give her healing less often to open up chances to punish her. Now the meta has shifted, and they are reverting the change.
I understand that you feel strongly about a champion you like, I personally am really loving Kayn and have some massive issues with his kit, but they are mainly on the QoL and visual issues with his passive, and I will wait for them to decide when to work on some buffs (I think he needs them, he's a relatively low winrate jungler and top laner)