It seems the current plan of record (after long discussion on IRC and upstream ML) would be to enable /tmp on tmpfs on vivid+1 (it's quite late to do it this cycle, even if we switch to systemd by default).
Upstream ML reference after another approach with a service to disable tmp.mount: http://lists.freedesktop.org/archives/systemd-devel/2015-March/028966.html
It seems the current plan of record (after long discussion on IRC and upstream ML) would be to enable /tmp on tmpfs on vivid+1 (it's quite late to do it this cycle, even if we switch to systemd by default).
Upstream ML reference after another approach with a service to disable tmp.mount: http:// lists.freedeskt op.org/ archives/ systemd- devel/2015- March/028966. html