On the contrary, it means that the printer is inherently unstable. HPs are notorious in that respect. Of course, we don't know until people get day to day print experiences, but it is not specifically a good sign...
HP's tend to be extremely stable in day to day usage. My designjet has never had a problem, and I've printed the same image months apart and gotten the exact same print. The closed loop calibration is a good thing in order to get the printer to "exactly" factory specs---I use it when I replace a cartridge. I've not seen any cartridges where I've felt that I've had to recalibrate---but it's just part of my workflow.
The closed loop calibration attempts to eliminate the variation in color with printers that come off the factory line, as well as eliminate problems with cartridge variability.
The issue of profiling is separate. Profiling a paper will (likely) give you a better print in the end, although the HP profiles are pretty good for the DJ series.