I've always found the Cincy un-built system facinating also.
Mostly because the same designers who designed the original unbuilt stations, also designed the section of the Cambridge Tunnel on the Red Line. So if you see pictures of the interiors of the unbuilt stations in the Cincy system. They are identical to Kendall, Central, Harvard (Pre-1980s remodel) minus all the tile work (it appeared that that was all that needed to be done in the Cincy system)
But also how it was built and never used. And how years of NIMBYism and just lack of general support has never gotten a subway to be completed or ever used. Then add some highway construction (I-74?) that demolished several outdoor sections. and it just sat unused for decades, until the city decided to run a water main thru it.
BUT.. since, unlike Kendall/Central/Harvard where the street level growth density radiates away from the station, in Cincy, since the system was never opened, growth happened everywhere else.
Of course by the time support for rail public transit was finally gained, the growth happened elsewhere, hence why the new light rail system doesn't really, and couldn't use the existing tunnel (even if the city moved the water main).
Its still a very interesting situation..