Taking it early is one thing, he used to just block a lot of his backhands back. He is now hitting through the backhand more while also taking it early. It is not an easy change that happens overnight, there are lots of timing and coordination issues to deal with.
I'm just saying that Thiem's results would improve if he took the ball earlier.
Not sure if I understand with certain what "block backhands back" it is. The only cases in with that makes sense if interpreted literally is slicing returns back or taking balls that land nearly on it's feet. These are a minority of the balls so this statement doesn't seem to make much sense. If you mean with that to be more agressive with it taking earlier, that's only partially true. On Australia Open Federer's hit through while taking early since many years ago, probably since they changed it's surface in 2009. In Indian Wells he did it mainly against Nadal. In Miami barely did it.
And he always did it many times here and there through his carrer. And Federer's new racket probably gives him more safety to do it now.
So, nothing as different as you imply. But yes Thiem can change it and improve his results. Unfortunatelly, more likely it will deteriorate his results. If he goes as far as taking his backswing, may even destroy his carrier.
How many times I have said that technicall improvements are nearly always small through a player's carrier? There is a reason players generally never try to do changes like these except, maybe, on serve. And the reason is exemplified by Gulbis .