hmm.. I have played around with my ADS sens as well, you have to account the fact they all use different mouse dpi's .. I can get used to Shroud's 1.5/800dpi pretty easily but I also prefer moderately high sens as well for the adding freedom of turning, etc. also makes looting way faster and way easier. I've just noticed that I will miss more precision shots from long range with a higher sens, it's just going to happen. I can use any auto but the longbow and wingman will see a difference- but the tradeoff is that I'll be more of a menace at shorter distances.
For the ADS specifically, I've tried diff variables of .9 to 1.3 in different matches. I recall 1.2 making a nice difference actually, I've used it more than once. It's all personal preference, I definitely have a run and gun playstyle so I needed to find a sens to suit me. I ended up leaving both at 1 (1800dpi). What you're theory-crafting makes perfect sense, but I personally don't like my zoomed ADS being really sluggish since people can dash and jump extremely fast