You have to read the book to know that it is NOT all about " style "... its very heavy on theory.. most of which is still in use today,, he was writing 25 yrs ahead of his time .
The tempi of dance, is in no way related to his explanations on how to achieve , for e.g. , " movement ". Nor is it part of the discourse .
And yes.. i would agree that the appearance has changed dramatically ( mainly thru the change of " pitch " ) and the lowering thru the legs ( italian concept )this has tried to set a new paradigm.. many agree, many do not .
There have been several articles recently about the very topic of " pitch ", and should there be a slight change in the fwd stance .
On that same vein.. the ladies "arched position", by some high profile dancers, is being severely questioned .
And, by the way, the rev tech. was written LONG before that.. would you discard that ?