Another thing for TJs theory.. Smaller rotors will dry off quicker in rain as there's less water to wipe/evaporate off.
Plus they will hold less grit (if you're riding in sandy conditions) and kill your pads slower.

Also.. Agree with the hope pad compound thing.. You've got to work damn hard to wear a sintered pair out… Shimano's though: nom nom nom…

anyone else have any thoughts on the effects of pad compound?

Pad compound will have a huge effect – it will alter the heat transfer and the heat range as well as the obvious effects on friction coefficient and lever feel.

Then you have all the variables of different types of pad – sintered, resin, kevlar etc etc.

I agree. I think that's probably got more to do with how brakes are reviewed/perceived than the design of the brake.