To bring this up to date..
It was all about control.
I don't know about fitter but Nadal looks worried at times now, glancing nervously at the shot clock, checking he's on time.
With his 'ways' he will not want to be breaking rules, getting penalised, having confrontations etc.
It's taken away his normal rhythm - taking pretty much as long as he liked before definitely gave him an edge, a pondus if you like.
Make the opponent wait, everything is on my terms.
Djokovic and his endless ball bouncing was similar and was I'm sure a control tactic - make the opponent wait and wait and wait and wait until he decides, and then bam, serve, maybe play, maybe a fault, then wait and the wonder when play will start again.
It was about being in control.
Take that away and the pondus and control is to some extent gone.
The this is my turf

or dirt as it maybe, here we play on my terms..
There is of course them suiting it to their own recovery times too.
They could try to slow their opponents down between points but that was harder.
Once on their server again it was back under their control.