I have never been bothered by the Series 8 filters. I have all I need. Heliopan & B&W still make them.- B&H sells them. As long as they are being made & used Series 8 filters are not "obsolete". I still use Series 7 & Series 6 & Series 5 filters.
Series 8 is "obsolete" in terms of being a royal PITA for many less-than-patient Hasselblad owners whose only lens that requires Series 8 is the old 50mm Distagon C. If all your other lenses are B50 or B60, that one Series 8 lens requiring a separate set of filters can be annoying, as nice as the Heliopan or B&W Series 8 filters may be. Yes, Hasselblad once offered some nice adapters to mount Series 8 on B50/B60, but... yuck. I'm certainly glad the expense and inconvenience aren't dealbreakers in your work, but some of us do find the filter mismatch irritating enough to choose a different version of the 50mm Distagon.
My hood has never gotten stuck.
Didn't mean to imply the Series 8 Hasselblad hood gets stuck: I never experienced that with mine, either. I was referring to generic 67mm threaded (non-Series 8) filters and hoods: these must be used very carefully, only screwed in a little bit, otherwise they can strip the Series 8 barrel threads and get stuck. These days, many examples of the 50mm Distagon C are missing both their original Series 8 hood and Series 8 filter retaining ring, prompting more and more Hasselblad newbies to experiment with generic 67mm accessories. That can be risky.
The knurled ring has never bothered me either.
This is down to sample variation and personal taste.
The metal knurled focus ring sitting flush with the camera mount didn't bother me nearly as much with my 80mm C as it did with my 60mm and 50mm Distagon C lenses. My Distagon C focus rings were even more heavily damped (resistant to turning) than my already-heavy 80mm C: that turning force combined with the unpleasant metal knurling scraping my fingers against the body were enough to finally move me toward the CF and CB versions instead. Regretfully, I must add: the build quality and appearance of the original C lenses is one of the most attractive aspects of the Hasselblad system. The later CF and CB versions are easier on the hands to operate, but never look right on the stylized 'blad camera bodies (plus the easily worn off cheaply-painted focus/aperture/shutter numbers and flimsy breakage-prone plastic barrel parts are appalling in lenses that originally retailed for more than the price of a used car).
I bought and resold five Series 8 50mm Distagons before giving up and moving to the CF FLE: two single coated silver C, one silver CT*, and two black CT*. Of these, four tore my hands apart during focusing and one was reasonably comfortable. My final black 50mm C T* had a velvety-smooth focus damping unlike any other C lens I've ever used. I thought I'd found my keeper, but then it developed an aperture stop down problem that David Odess quoted me $445 to repair. Given it was easy to find clean 50mm CF FLE lenses for $699 at that time (six years ago), I took it as an omen I should migrate to the newer, uglier but more ergonomic CF lenses.