The difference between Nadezhda Pavlova's high extensions and current useage, is that Pavlova as she matured had a totally feminine shape with a fully integrated technique, in which each movement flowed with great musicality and was not punctuated by a gymnastic emphasis.
"…in which each movement flowed with great musicality" - what a wonderfully precise description of her dance!. Yes, yes, integration, musicality and heightened femininity is how I would also describe the wonderful quality of Nadazhda Pavlova's dancing manner. There is also certain vulnerability, fragility even, that makes one want to take care of her.
Alas, I probably wasn't even born yet when Nadezhda Pavlova was at her peak, but whatever footage of her dancing has survived, moves me very deeply. No other dancer either past or present, has such an emotional effect on me.
As for that extension business … I believe that it is much ado about nothing. In fact when I watched Nadezhda Pavlova in The Nutcracker
(on DVD), it didn't even occur to me that her extension was particularly high. And only having read Leonid's post, I had to go back and see for myself just how high it was. This tells me that the movement by itself is neither good nor bad, but has to do with how it is being used. The same can said about double and triple fuette turns.