I think what we’re seeing is the difference between 35, SK attempting to time on the equipment of the day, MGMs 65 scan and eventual attempt to match SK’s timing and then WBs now outdated higher res scan of the 65mm elements. This is why it lacks all the coloring of the others and is limited to 2k.
Like many other WB transfers, the color is missing due to using higher negative elements and at times it appears some non-original tints have leaked in. They should redo it at some point isn’t he near future as other Kubrick titles have been hinted at or done such as ACO in 4K. Many of the others are equally if not more problematic and all based on old work.
The 1990 print being in Dolby 4-2 is correct as then no one would have been able to mix in the old Todd-AO system of five-one. Plus I think it might suit the film a tad better by isolating the low bass-not that I like losing the LC and RC channels.
Until they do new work we are stuck with these. Utilizing the Bluray and adjusting the color timing whilst adding the MGM PCM (less damage than CC) and 5.1 ac3 for theatrical approximation is about the best we can do. Once this is done perhaps we can then try to tackle a mathematically correct smilebox version.