A brief and totally weird anecdotal thing:
I've handled a lot of dogs (including other sighthounds), and the handful of Borzoi I've laid hands on (all "purebred" AKC versions) have all felt... funny to me.
They're large dogs that look like they're supposed to be smaller, somehow. They're spindly and narrow, with wispy hair with that weird (and totally unnecessary) humped back and under my hands they feel... too light. Like they have bones made of balsa wood, or they're actually hollow on the inside. That ridiculously extreme roman nose seems like it's full of air. Certainly, they feel delicate: fine china that would fall apart with too much pressure. Now that I'm writing this out, it occurs to me that all borzoi I've met, no matter the age, feel the way an old or sick dog does under your hands.
My friend and fellow vet tech Joellyn once told me she "prefers a dog she can thump on" (and then gave an affectionate thump on the ribs of her border collie for emphasis). I feel the same way; I don't like tiny shivery dogs.
I don't feel like AKC borzoi are dogs that can be thumped on.
Kind of sad for a breed whose other name is Russian Wolfhound and that supposedly descends from great and tough hunters of the Russian plains.
I wouldn't have thought of this at all, except I saw this recent post about some "real" borzoi (as in: non-AKC dogs in their country of origin, doing the job they were bred for, instead of being overbred to look a certain way for a show ring):
Now there's a dog you can thump on.