Yes, but Ali and Mandela don't count, because they're already dead!
So let's go with the discussion you had with your missus. Whose death now, would have the biggest impact (for good or bad) on the world?
Yes, Putin.
I went with the discussion you had with your missus about whose death would have the biggest impact on the world. Ali's death has not changed the world. You also wanted someone who is still alive, so that counted out (no pun intended) Ali and Mandela.
The way Putin is ruling Russia...