As a person with 93K and R7 mastery on kat
DO NOT BUFF KATARINA Keep her where she is she is really good if you know how to place her daggers and her combos
Her consistent damage is solid you shunpo like 7-10 times a fight
There is literally so many different ways you can use her daggers that it would take a while to list the many situations
People say her laming phase is weak I say the complete opposite you have a good outplay potential and damage for trading in most match ups
, also she has extremely go chase potential especially with her W giving 90% movespeed bonus on cast at max rank is pretty strong.