Nonsense. Every person's balance and movement pattern is different, and therefore you should never try to copy someone else's movements as it will not work. You could look to Fed's footwork etc for tips, sure, but ultimately you have to play to your own body's strengths. That is one of the reasons why Grigor hasn't achieved anything yet, his mind is too locked in trying to imitate Federer instead of finding a game that comes naturally to him.
A kid who doesn't know which hand is which doesn't have any balance and someone needs to teach him how to play, how to position himself, how to swing at the ball.
My generation was taught the Lendl style - FH - left leg toward the net, body parallel to the side, etc.
I was questioning myself later - why Agassi has a different position then? Then Courier confirmed my doubts that my coaches were noobs and i started playing like this myself.
Now Roger illustrated how it's perfectly done, for all shots that exist in a book of tennis (i would question only his BH volley, but this is too much into details to start a conversation here), so everyone starts trying to play this way and then his body and mind change these settings in the way it's more comfortable for the player.
Of course, more comfortable doesn't mean better. My kid feels most comfortable kicking the ball with his toes and i try to explain him that it might feel weird now, but kicking it with the inside and upper part of the foot is the better way for him..
That's why a magicien like Santoro couldn't ever do more than he did, despite all the tons of talent in his hands - coz a mug coach, with Connor's BH in mind figured that if the kid has it from both sides - he can't win less than 10 Slams...
Grigor has mastered the ultimate correct tennis style and he'll be up there winning Slams one day hopefully.