While the Otus is appears to be a technically phenomenal lens, it strikes me that to actually realize its distinguishing benefits you have to use a tripod. Because most 50mm lenses in good condition built over the last 50 years are quite capable of taking very sharp photos if used with proper technique, I suspect that one might not see the difference between the Otus and other 50mm lenses as a practical matter unless one is using a tripod or a really fast shutter speed. Of course, this negates one of the major advantages of a 50mm lens -- size, portability and spontaneity -- which to my mind are much more important to one's photos than sheer technical quality. The Otus, which is pretty huge and heavy, could be seen as technical gear obsession taken to a new level.
Most lens reviews these days are flawed in the sense of concentrating almost exclusively on technical image quality. Far less (or no) information is provided as to how easy it is to focus a lens, its balance (which affects one's ability to hold it steady), etc. which factors are probably much more important in actual photography and in distinguishing among various lenses, especially since most lenses made in the last 50 years are technically good enough for 98% of the photographers out there.