You're probably right Christoph (or is everybody in holiday). I personally never had any issue of this kind, out of making a system cache reset at the very beginning to get the monitor out to work (with the very old FW). I also had corrupted rigs and I just deleted them, but my Kemper keep sounding as good as day 1 (actually better with all the upgrades). Some user have managed in the past to borck their units and re-installing the FW resolved the issue but that's all...
I had some issues initially in the first few firmwares and thought it would be good to try the reformat procedure. Primarily I was having the warbling/alien sound on the high strings. Boy was I wrong. It was foolish in retrospect and the issues seemed to have been resolved with firmware updates and just doing system resets rather than reformats. I think CK is right to downplay the utility of a reformat. My KPA actually sounds better than day 1 because of the firmware upgrades and learning how to dial it in :).