Before you get too excited, I doubt that the problem with some fragile surfaces is fixed, but I had a issue with my 44" model that was serious enough to cause problems on HP Professional Satin Photo Paper. In general, I love the finish of this media (I haven't got my Harman Gloss to try yet), and have had few issues with it, but I had an extremely light linear rippling across the width of my prints and a more serious soft indentation at 18 1/2" from the right side of the paper. The stripes were not serious enough to notice except in the reflections, but they were bad enough that I could not sell them as fine art prints.
I had read about others issues with the star wheels, and experienced my own issues across the surface of the whole print on a couple of glossy stocks, but I thought it was worth a shot to see if replacing the star wheel assembly might help my particular problem on this heavy stock, since it was not a problem across the full width of the paper. I called HP yesterday afternoon, and in less than 24 hours a technician was here with a new part to install. In my case, the new assembly completely solved my problem.
I have 17 44" x 60" gallery prints to crank out by Tuesday or I would test it with other stocks, but will try it with other papers when I have a chance. The technician did not know if this was the same design as the one that was replaced, so I don't know if this is cause for optimism on all fronts yet, but I felt like HP took care of the problem as fast and efficiently as I could imagine, and I'm a happy camper if I can get this show printed with no other issues. I think the moral of the story is to certainly pursue a solution with them whenever you have a problem and to not be complacent with manufacturing or design defects until you have at least attempted to have them fixed by HP.