> So, making /bin and /sbin self-contained without requiring /usr would require expanding the "minimal" root filesystem to include zlib, libcrypto, PKCS#11, PC/SC smart-card support, gnutls, libtasn, libnfnetlink, several glib libraries, gio, dbus, and OpenSSL.
You say this like it's ridiculous, but I don't see a big problem. On one of my systems, also Debian, I have 10 binaries in /bin or /sbin which need /usr, on another I have 11. They depend, between them, on 22 unique libraries. This seems like a small problem to require such a big solution.
"10 of 332 binaries in /bin and /sbin require /usr. Obviously the correct solution is to get rid of /usr and merge it into /, and not to move 22 libraries into /lib/" - does that sound right?