I'm mildly surprised. There are a surprisingly large number of Hellraiser sequels already, and many of them did poorly. I believe that after the truly dire Hellraiser 4: Bloodline they stopped getting theatrical releases. I've seen HR5 on DVD and I couldn't 6, 7 or 8 anywhere last time I looked.
HR4 is the one that most neeRAB to be expunged and remade. I actually quite like the idea of there being 3 sections, and showing how the lament configuration originally came to be made.