I've now done lots of still comparisons with WOWOW vs. grade-matched BD and I can honestly say that the WOWOW, surprisingly, has more detail.
The software I use for the MatchGrade also has a basic image registration algorithm, so the stills used for my comparison were spatially aligned rather well.
The difference is striking.
I'd like to despecialize the WOWOW, but I can't without access to that 10 year old 1080i MPEG-2 ABC TV broadcast version capture. I'm still digging, but I haven't had any luck yet.
For now we may have to settle on the 2003 "enhanced" version.
I still have to remove the burned-in JP subs from those shots. I may seek outside help to get it done well.