I have a few ideas:
1) Amp EQ controls- add the ability to adjust/change their range, or better yet have presets for popular models with their known EQ knob control ranges like Marshall, Fender, Boogie. I've had my Kemper for at least 6 years, this has bothered me from the moment I first plugged in! First reaction was this isn't right. The Mid control especially, doesn't sound like a mid from any amp I've ever played, it's so off and unuseful. (granted played mostly Marshall and Laneys) If there was a dropdown in Rig mgr where you could shift the eq knobs frequency range around, or ability to load real amps tone stacks values would be better. I basically keep all these controls at 5 for most profiles. Yes, you can use EQ in other places, but the amp EQ knobs are what most guitarists know and reach for.
2) Pannable effects- the ability to pan a reverb, delay, etc. all the way right or left. Yes, I know you can do this in your DAW, but it'd be cool to have on the Kemper. One of my most favorite and most legendary guitar sounds is Van Halen 1. The dry guitar sound is mostly panned to one side, and only reverb panned to the other side, totally separate. So it sounds awesome together, but the reverb doesn't cloud up the guitar signal. Even better, to reverb, delay, maybe flanger, phaser, add a dry pan, and a wet pan knob to each, then you could have total fx pan control.
3) Output section- add a Digital fizz remover for recording purposes. Some of the high whistling frequencies which sound harsh and fake in digital compared to analog signals could be lowered. I.E., 3k, 5k, 7k, some slight dips there added as an output control. I'm sure Kemper experts could identify the most likely fake and harsh sounding frequencies, and create a control just for lowering them. Another one you could do in the DAW, but it would be cool to have on the Kemper for recording and live use. This way you wouldn't have to turn down the high cut so very low. You could call it Warmerizer, or something like that.
4) Better, much more accurate profiling process. Better, more accurate refining process, or some way to standardize it.
5) Add ability to record and re-amp through the USB connection, and for Kemper to be an asio option in the DAW.
If any of these already exist and I missed it, let me know!