Good video, HW. Thanks.
My experience with real tube amps is that the "sweet spot" for maximum gain is where notes are still clear enough to be intelligible, but going any further into over-saturation becomes destructive to crunch and note distinction. Obviously different amp designs have different responses to saturation. A multi-staged amp can have incredible distortion crunch without "mushing out".
So my (admittedly limited) experience with the Kemper is that I audition profiles looking for how my pickups saturate the profiled amp for maximum breakup with the best tone and dynamic response. And because I find better tone out of my pickups when they are lower than I see most pickups set, I usually have to select a profile with a higher gain setting used during the profiling process. Yes, I adjusted the input section's "Distortion Sense" to what I "think" is enough compensation, but I have no way to verify that it is set where it would be "equal" to any pickup output done by the profiler. That is one "level meter" I wish the Kemper had available...a target input gain meter.
The bottom line is I pick the best sounding gain breakup profile I can get and work DOWN the gain from there. Dialing back my guitar sounds great like that. Just like the video shows, it sounds better that way. When you push the gain up, that is when the pick attack gets weird sounding, and something doesn't sound natural about the breakup. So I agree with HW about that. I hear exactly what he is illustrating. What Don is saying about "tone" is also true, but the attack and dynamic response is what I hear falling apart when you push it further up beyond the optimal saturation point. Real amps do not respond the same when pushed up more. That's my experience. It is what it is, and I can live with that. Nothing comes closer to real amps IMO.
If I were doing the profile, the perfect point of real amp saturation with my pickups would be achieved. But since I have to work with what is provided, I can only select a profile that is closest to what sounds like "max without mush". I will try to push up gain and find the proper dynamic response point, but sometimes you just don't hit it right. And of course this is all subjective stuff. What I like might not be what the profiler likes, so that could be a deal-breaker right there. The ones that work well are beautiful though. Pure sonic enjoyment!