I have openSUSE-11.4-Tumbleweed, no factory, but I see it coming in Debian unstable, this FileHierarchy change:

/var/run
/var/lock
/dev/.udev
/dev/shm

change to:
/run
/run/lock
/run/udev
/run/shm

This is beautiful, because you don't have temporary trees all over the system any more, you just can mount one tree as tmpfs. But there is one ugliness, why was not /var/run changed to his own tree, like /run/current

My two points:
- Debian unstable mounts various different tmpfs above each other for different sizes and restrictions of /run,/run/lock,/run/udev,/run/shm
- All run directories, previously sited on their own (/var/run), are now above /run/udev and /run/shm. Could this accidently provide security issues?

My one cent:
This structure as decided from Fedora, openSUSE and Debian is not as beautiful as it could be ...

My first incident:
A chroot to Debian unstable has no "aptitude" (zypper like tool) any more, because it needs /run/lock, which is not available in a chroot (/run/lock is created at boot). I expect more difficult bugs on the way to /run ...