Slow startup has been the "elephant in the room" for a long time. There's no justifiable reason why a small computer in the twenty-first century should take over a minute to start up.
And just because there *is* a dependence on rig count doesn't mean that there *must be*. Think about it: if the KPA is reading *every* rig on startup, then that could be done *one time* and the pertinent data stored in an index so the work doesn't have to be repeated on the next boot. Hey, there's even a real-time clock: the Kemper could easily detect when the rig directory has changed and update the index accordingly.
Looking at this from the perspective of other "high-end" guitar processors: My Eleven Rack boots in 15 seconds. My Axe-FX boots in 7 seconds. (While I'm new to the latter, I understand that there were howls of protest from the user base when the AFX boot time increased *to* 7 seconds...)
On the other hand, I suppose I could buy a second KPA *and* a UPS, reserving the second KPA as a "hot spare" just in case I didn't want to wait for over a minute in the (thankfully, exceedingly rare) event that a glitch takes down the active unit. Hyperbole? Sure. For me it is. But I'm certain that touring techs lose sleep over scenarios like this... OTOH, never mind: if a touring band can afford a tech, they can certainly afford to pay for redundant hardware...
Seriously: fix the ridiculously long boot time. It's aggravating. Even a tube amp can be ready to play in eleven seconds.
I wholeheartedly agree with all the above statements. There is no possible reason that it has to go through every rig on startup. I also like the fact that on top of saying it doesn't need to, you actually offered an idea on how to fix it.