What do you mean "already working" or for that matter why is fixing in quotes as if you mean breaking. There is already a list of many things that would be broken in a default system if /usr isn't mounted both on freedesktop.org and even in the comment thread. That means /usr is currently _REQUIRED_ to be mounted in early boot or some parts of the system will be broken. Since a working user is required to have a fully working system, and has been for some time now, then there is no justification for having a separate /bin, /sbin/, /lib. Standardizing this in one place, as has been done on other UNIX OSs, fixes a bunch of corner cases, opens up easier setup for having the system files on shared/networked storage and _can't_ break anything because there are symlinks from the original location to the new standard location. This is all upside. People do like their bike shed arguments though.