Requesting Context Concerning Katarina Nerfs on the PBE

Why Nerf her ult cool down by 30 seconds at rank 1 and drop the base damage by 50..? Cause her early game/ and landing phase aren't bad enough already. Recently Riot has been taking the "don't just nerf champs" approach and trying to reevaluate a champs strengths and weaknesses. This change is hypocritical of that approach. Riot has always stated before that they want most of Kat's damage to centered around her ult making her a "high risk, high reward" champ because playing smart rewards the player for being able to deal a lot of damage with her ultimate. This change is a straight up Nerf with no compensation at all. And Riot refuses to buff her basics abilities due to the nature of the reset mechanic on her passive. Some context from Riot concerning this change would be greatly appreciated, because I am really confused about this change taking into consideration what they've said about Kat in the past.