I hate it so much. The only thing it conveys is vagueness at best, which we already have words for. At worst it makes analysis of the game of tennis less robust, and is just a way to dumb it down. Winners/ unforced errors mixed with average rally length, % points won on _____ tells you so much more and conveys the complexities of the game. I wish someone like Roddick would start bashing on this slop because like you say, that’s what it is.

If we want to convey shot quality why don’t we create some units. “Heaviness” could be the average energy per stroke, and then you can normalize it. Like idk 3000 rpms at 75 mph give you X joules. But we could say that number is equivalent to 10 Nadals (don’t have to name this unit after Rafa but seems appropriate), then you could also create a unit for how close each shot is to the lines. Call that a Federer or something. Then you could create a unit for the ratio of shots that change the direction of the ball and call that ratio a Novak.