Interesting thread but I think a few things need clarification.
Half-Speed Mastering by itself does not increase the dynamic range (DR) of a vinyl record. It slows down the cutting lathe which results in greater micro detail. The DR of the vinyl record can be improved by putting less minutes of music on a side or by speeding up the playback to 45 rpm but those options have nothing to do with half speed mastering.
The mastering process for a vinyl record can be more complicated than for a CD. The engineer making the master disc may use EQ to reduce the bass for loud passages or compression to fit more music on a vinyl record. There is a famous story of the first Led Zeppelin release where the record company executive gave the album to his daughter who had a "kiddie record player." Due to the heavy bass the tonearm wouldn't track and it skipped. They immediately remastered the record to reduce the bass so it would play on all turntables. If you are lucky enough to have one of the few original pressings you are a rich audiophile because collectors would sacrifice their grandmother to get one. Michael Fremer has a video about this. The original master was used for all subsequent releases until Led Zepellin decided to issue a remastered series on CD that restored the original bass EQ.
I have never seen one shred of evidence that vinyl inherently has greater DR than CD. I have also never seen any evidence that CDs are generally more compressed than LPs. There may be some cases of this but it is phenomenon that only applies to individual titles. There is no reason why a mastering engineer would compress an album more for CD than for LP.
Compression relating to the "Loudness Wars" is a completely different issue. Some time around the mid 80's the record industry asked mastering engineers to use heavy limiting to make music sound louder for the radio. The techique was also used for remasters of older titles to make them sound more punchy. If you compare a heavily limited remaster with the original vinyl release (pre loudness wars) then the original vinyl will have a greater DR than the remastered CD. However, I can find no evidence that a current title that is released on CD and vinyl has a greater DR on the vinyl version. If someone wishes to make that claim then they need to provide evidence. I looked up several titles on the DR Database and could not find a single example of the vinyl having a greater DR than the CD if both were released at roughly the same time with the original mastering.
Lastly, there are a whole bunch of factors that go into an audiophile reissue. Half Speed Mastering is only one factor. The mastering engineer may have changed the EQ and compression, the electronics in the mastering chain may be better, the quality of the master disc may have been better, they may have pressed fewer discs from each stamper, and the quality of the vinyl may be better.
