it's probably done before but I would like to know what you think which is the best asset of a player of your choice. I think it will be hard to come to an agreement with most players.
For example Justine: is it her backhand? Or her variety?
Serena: The serve? Her will?
Of the not active: Graf: The forehand? Or the footwork?
Go ahead and have fun discussing. And please don't fight...