Kha'Zix passive

I have an idea about passive. The passive is good for masteries Thunderlord because it activates when you exploit the Q and passive, but if you Thunderlord the coldown,you will not have the purpose of passive. So I have an idea that other passive beside the present is that after the killing you can take something like a stack and add it to the passive, it will increase the damage on it.Stack you can pick the Campion while you killed is not respawned.Of course, after kill you can take only 1 stack.What do you think about that