So I ran across this at reddit, but it looks like the gnome team at debian might skip gnome 3.10 and go straight to 3.12. Looks like they delays are attributed to glib and the init debate, which I am sure most of us figured.
Post is here; http://www.reddit.com/r/gnome/comments/1y1yaq/why_are_gnome_releases_on_debian_delayed_so_much/ the comment is by bigon but I can't say for sure that he is a debian gnome maintainer.
Bigon works on debian-systemd.
greetz
devil