I love my Kemper but where I could see useful improvements in a Kemper 2 is:
Better dynamic range. On just about every profile there is a static quality to the sound and feel where the tone is not nearly as touch sensitive as it is with a real tube amp. With a real amp, when you play light there is one tone and as you progressively dig in, not only does the sound get louder, but with many amp and settings, there will be progressively more gain as you dig in.
I would also like to have mono and stereo effects loops usable at the same time.
Lastly, it would be nice to be able to play 2 profiles at once and add to that stereo inputs so that if you are using a guitar with a piezo pickup, sending that and the magnetic pickups separately to two different profiles would be very cool.