They have fun in practice (beause they mess around most of the time) but they complain in matches asking me why they lose. And when I watch their matches, they completely dump their backhands, so what am I supposed to say? I use a one-handed backhand so I know how tough it is, but they aren't using backhands; they are trying to play racketball on a tennis court.
Professionals still virtually all follow the same techniques for every stroke. Obviously there are a few outliers such as Santoro, but even if you watch Santoro, the basic mechanics he uses are practically the same!
Tell them to quit F***ing around.