I think that I,ve found the solution for the problems caused by different types of guitars:
a good, easy configurable EQ in the inputs menu.
I have tryed the Kempers EQ in the A stomp to reduce a little bit some guitars muddiness or cheapness, and it was working somehow,
but whith a Boss EQ pedal inserted before the Kempers input I was able to make miracles! No more twang or boominess, no more cheapness.....and I can reduce some of the low range guitarnoises too!
..............The only problem is that I don,t want another gear in my setup.
Mr. Kemper, can You insert, please an EQ in the input menu on a future software upgrade????