Check out the R_U_Sirius Bogner Shiva rigs. Very wide range of tones here. If a rig sounds too harsh check the Definition parameter in the Amplifier section. Then try to optimize using the gain setting and treble and presence controls.
Your perception of the tone could also be influenced by what equipment you're monitoring through. What are you using? Studio monitors? What kind?
Another thing to consider is that the Kemper reproduces a miced guitar cab sound which may be different if you're used to hearing guitar "in the room" with a traditional amp + cab.
Basically, what I'm saying is that you should be able to find plenty of profiles that offer a smooth type of distortion. If not, something's off with your equipment or your ears. Not meant to be harsh, but it's the truth.
In addition to what HELL-G mentioned above, sometimes lowering the high shift a bit in the cab section helps to tame the highs with some profiles.
a good distorted profile like the mentioned and in my opinion the plexis of and44 or darrcooper (and44 is commercial while darrcooper is free on the RE), but most of all your hands.........I sound too philosophycal, I know. but that's the reality: it's in the hands 
- Fiddle around with an EQ or overdrive before the amp section, boosting and cutting to see how it affects your signal. I've found the Treble Booster stomp, not cranked up too much, can be really useful for getting more of that clear, brand-new-strings attack in your tone.
- If you've got the rig set so that it sounds nice, but the distortion is the wrong flavor, try turning up Treble and turning down Presence, or vice versa. By doing this, the overall brightness of should stay reasonably consistent, but you'll be adjusting which bits of the highs are getting through and therefore how much grain/etc you can hear.
- As noted above, Definition is great for adjusting how your rig is distorting. Turning up Tube Shape might help you out too, as it should take the sound from preamp distortion (modern amps) to power amp distortion (older amps). All of the amp section's parameters are good here, really.
Are you comparing to recorded tones or real life tube amps? Because recorded saturated tones almost always are a combination of multiple layered tracks that give that saturated effect. Usually recorded with a lower amount of gain than what you'd expect.
Some type of genre should be good to know too. No point in suggesting an Engl Powerball profile for blues. 
Maybe silly,but: You have CabSim on, do you? I once forgot to put it on again after playing over a cab and when I connected it to my CLR again it sounded like a chainsaw.
Some really useful responses here guys thank you very much - just delving into some of the parameters mentioned has already shifted the sound towards what I'm looking for.
Definition and some of the tube settings have softened some of the rigs nicely, once layered there's been a noticeable improvement.
After owning the Kemper for two months I've decided to start reading the detailed PDF manual.....
I agree with one of the early posters - what are you playing it through? I tried using a guitar cab, and it sounded kinda like you described, harsh, shrill, painful to listen to. If you play through studio monitors (they don't have to be expensive ones), with CabSim "on", you should easily find some great-sounding profiles. I have some profiles that sound SO good, and I'm playing through 5" monitors (Rokit 5s)
in addition to the manual(s), there's also wikpa.org
Probably fringe, but in case these could help...on my guitar with a hot pickup, i find it more tubey if if i lower the pickup height ie increase distance from strings. On some rigs, i like to put the Soft Shaper boost at very very low drive setting in x slot which is after the amp.
Thanks I will try that as well 
Good to hear. So go, rock
