This is fantastic logic and convinced me to move off of my software raid using Windows Storage Spaces and back to just a bunch of disks mapped to folders. I gained 1/5th of my storage back and I found a disk that was almost dead in the process - when it died, I would have had to scramble to replace it or risk losing the whole array. Now I sleep easier knowing that if a single drive dies, I just replace and replot it. Works especially well for me cause I’m targeting lots (60+) of the smaller renewed drives that are still available using SATA port multipliers and a custom “enclosure”. 
This specific use case is quite different from any other data storage and sometimes it takes direct logic like this to open one’s mind. Thanks @vitekorre!