I think our definition of hard work may differ significantly. I agree that the the K is slower into corners, is heavier overall and takes more wrestling to flick (haul?) from bend to bend but, for me, that's only one aspect of the overall road riding process. The ability to use the torque and avoid gear changes, the ability to ride for a full day then get up the next morning ready to do the same again, the ability to filter down through lines of traffic in town, the ability to see what's happening behind by just looking in the mirrors, the ability run at autobahn speeds for long periods of time and the ability to confidently put a foot on the ground when arriving at a junction with a wicked camber all make for a bike that isn't hard work.
I've not owned a XR and I've only had a couple of test rides on them so my experience is limited but, while it is a great bike with many "plus points", for me it most definitely was not "less work" than the K. In fact, the K, despite it's age, was, I felt, definitely an easier bike to live with. But, each to their own.