OS 7.5, which comes soon, will have a delay widener effect that does just that. You could currently do it with stereo delay and set one side to 0ms and the other to your favoured 5ms.
A bunch of the effects in the kemper already are stereo - in the manual from the Phaser (on page 170 ) onwards . I think putting them before the amp block may end up summing them to mono though - put em after the amp 
Be mindful of phasing issues when delaying one side. Further down the signal path (somewhere you may not be aware of) the non-delayed + delayed signals could be summed and introduce some unpleasant side effects. Yes, it does sound big when hard-panned L+R but i believe it’s important to maintain mono compatibility where possible.
Be mindful of phasing issues when delaying one side. Further down the signal path (somewhere you may not be aware of) the non-delayed + delayed signals could be summed and introduce some unpleasant side effects. Yes, it does sound big when hard-panned L+R but i believe it’s important to maintain mono compatibility where possible.
Good point when you are playing live and cannot guarantee what is happening with the house PA. Apparently the new Phase Widener in 7.5 is mono compatible though.
You can only guess, but the acoustic sim has been seen for months in clips and sounded amazing from the off.
There was one other thing in 7.5 with high and low pass filters added in various places. I think it was the master outputs and cab section?
I run stereo with hard pan L&R with a delay of 12ms on the R channel. The other guitarist is mono but I split his signal and delay the L channel by 12ms. The delay is 50% of the distance in feet between the FOH Mains x 1ms. Our mains are typically 20 to 24 ft apart. This produces the aural illusion of guitars panned left and right but both guitars still have equal volume on both sides of the room. Anything above 20ms doesn't widen the image much more. You'll need a digital mixer with channel delays and twice the number of channels than you normally need.
I use this same trick on every signal except the bass drum and bass guitar. Shorter delays bring the aural position closer to center. Every instrument and vocal is placed aurally in the same position as they are visually located. The drums are the same way. The final touch is to delay both mains so the stage sound aligns with the mains which is more important in smaller venues where the unamplified drum sound mixes with the mains. The drums are usually 12 ft behind the mains so the mains are delayed 12ms.
Yeah, I'm an anal audio engineer but damn, it sounds good. Huge difference. The PA becomes more transparent since the sounds appear to come from the positions of the instruments. This is effective for anyone sitting anywhere but the left or right edges of the room. On the outter edges of the room, it doesn't help but doesn't hurt. Panning always causes loss of volume somewhere...don't do it.
Be mindful of phasing issues when delaying one side. Further down the signal path (somewhere you may not be aware of) the non-delayed + delayed signals could be summed and introduce some unpleasant side effects. Yes, it does sound big when hard-panned L+R but i believe it’s important to maintain mono compatibility where possible.
What slateboy said.
