If you havent read already, riot has seen this mastery still being strong and plan to nerf it again
my two ideas (Which can be adjustable)
Im bad at explaining but:
1. If you hti one person with it, it gives eg 2% of 2% of each enemy champion, if you hti two, it will bump up to 3% of 3% of every champion (Worst explainer ever)
2. make it scale with level, like a few other masterys, so level 1 it could be 2%, but at later levels it can increase to 5%, so its not strong at all stages of the game.
Those are my two ideas, worst explainer, but i feel like one of these could balance the mastery once and for all