Strong disagree on pretty much all of this. The idea that US whiskey is more viscous than Scotch sounded so batty to me that I just checked, with a Willett, a TH Saz, and a GlenDronach 18; the Dronach is the leggiest of the three. (The Dronach is
obviously not the best of those three whiskies.)
I think I don't believe you that viscosity is a simple function of evaporation.
Think about it: in both US and Scottish whiskey, the spirit going into the barrel is much higher proof than what's in the bottle, or what you should reasonably drink it at if you've got a cask-strength bottle. If "good whiskey" is "thick whiskey", where "thickness" is the amount of water the distillate had lost relative to alcohol, then we'd all just be buying the highest proof spirit; you could treat the ABV like a point score for quality. Both US and Scottish whiskey is diluted to a place the distiller wants it to be at.
We also wouldn't need tasting notes describing the legs, because if it's just about evaporation, then it's purely a function of ABV, and that's printed on the bottle!
Certainly the idea that one should evaluate a whiskey based solely on its legginess finds support in zero whiskey sources I can find.
I don't just think Pappy is overpriced Veblen whiskey that people overpay for because it's the only brand they've heard of --- although people absolutely do that, and secondary market prices, which are the only place you can reliably buy the stuff, make it one of the major rip-offs in all of spirits. I also think Pappy is inferior to Weller. Maybe I've just been given flawed bottles; the 20 literally tastes like grass clippings, and I'd take a FR SB over any of the other Pappies any day.
At any rate: Scotch is not "all about the peat". You have to not drink a lot of Scotch to think that. Which is fine! Just moderate your stridency a bit. :)