There are no plans for a GNOME 3.0 release at this time. The GNOME community believes that regular, reliable, iterative improvements are more important to our users than ground-shaking major releases, and that we can more comfortably deliver major features -- when they're ready -- in our regular, six-monthly releases.
We made a substantial API/ABI break for GTK+ and GNOME 2.0, which was a massively beneficial change for our platform, and has allowed us to maintain a stable branch for a significant period of time. We're still deriving enormous benefit from the break and the stability. As such, we do not plan to do the same again soon.
A major rewrite or API break won't provide any benefit to our users, contributors, or independent developers creating software based on the GNOME platform.
A major rewrite or API break is not at all necessary to achieve our goals for or enhance active development on the GNOME experience in the forseeable future.
A major rewrite or API break won't have any positive impact on the broadening ecosystem around the GNOME platform, such as activity around mobile and embedded device development with GTK+ and GNOME.
The previous contents of this page can be found on the [:ScratchPad:scratchpad], where handwaving and ideation can grow and flourish without being confused with plans for the project at large.