debootstrap in unstable can now install with merged-/usr, that is with
/bin, /sbin, /lib* being symlinks to their counterpart in /usr.
LWN.net published an article in January 2016 going into this then-proposed change.
Debian is the latest Linux distribution to consider moving away from the use of separate /bin, /sbin, and /lib directories for certain binaries. The original impetus for requiring these directories was due to space limitations in the first Unix implementations, developers favoring the change point out. But today, many of the services on a modern Linux system impose requirements of their own on the partition scheme – requirements that make life far simpler if /bin, /sbin, and /lib can be symbolic links to subdirectories within a unified /usr directory. Although some resistance was raised to the change, the project now seems to be on track to make “merged /usr” installations a supported
option. And perhaps more importantly, the arguments favoring the merge suggest that many Debian developers would like to see that configuration eventually become the default.
Any steps to clean up Linux’ FHS implementation – no matter how small – is cause for widespread celebration all across the land. Call it forth!