Why ruin their experience just for your ego trip of having a nice sound on stage?
I have to agree that when using the KPA with cab, the monitor out EQ is your best friend (I usually cut the bass and boost the mids quite a bit with a closed back 4x12 type cab). However, whether it's with real amps or Kemper, if you can't get a good stage sound to start with, it's a little naive to think it'll be great out there in spite of all the FOH magic.
Someone who has played with real amps for a while will know what sound to look for out of the Kemper. These are generally not the sounds that provide "instant gratification" when noodling on your own. In my experience, even some of the big commercial profilers' material or some stock profiles are often not very well suited for live performance.
At first I recorded my (smaller) gigs and listened back to find out what worked and what didn't. For example, I'd put 3 or four slightly different profiles of crunch in one night and by listening back, find out which one works best and why. Rinse and repeat until you know what to look for. A year later I look back at my first performance profiles and usually they feel compressed, have too much gain and bass/treble. Still figuring out the perfect settings for reverb and delays. Now I stick mostly to one commercial profiler that I know is going for the same sounds I do.
I think lots of experimentation is beneficial, so even if you think one patch is good enough, you can try another one slightly different another night. If you can make it shine in an unfavorable environment, you'll also shine in bigger festival/stadiums with a top notch sound crew.