The GNOME 3.10 desktop environment is not even released, and Matthias Clasen has already announced the goals for the next major release, GNOME 3.12.
For the GNOME 3.12 release, the developers will concentrate their efforts on fully porting the desktop environment to the Wayland display server, which will be supported by default instead of XOrg.
The GNOME 3.12 desktop environment will integrate support for Facebook photos in the GNOME Photos application, add a standalone GNOME Software application for easily installing GNOME apps, integrate systemd support for the user session, and integrate Git in the developer experience.
Moreover, the upcoming GNOME 3.12 desktop environment will bring color tinting support in GNOME Shell, Zimbra integration, as well as a Videos application.
The development cycle for GNOME 3.12 will start next month. GNOME 3.10 will be officially unveiled in two days, on September 25, 2013.