I haven't played R3HD... Did they make better use of the score ratings then?
As for DOTK part 3, I don't know how deep into the score thread's history you've read, but the area was historically a hot topic for potential missing rooms in the game. We used an IPG-style glitch to explore part 3 in depth, internally and externally. Predictably, nothing came up (which was quite saddening really) so I've since regretted that initiative. Admittedly though, it's possible that a green gem could get teleported in or something similar, but we pretty much concluded it was a design fault from the developers...