The only noteworthy addition to Wayland/Weston 1.0.3 is having the Weston Test Suite under control for testing the implementation for fending off regressions. Aside from the test suite rewrite, there's just been some bug-fixes and other minor changes (like Coverity fixes), but nothing really exciting. Kristian pretty much expects this to be nearly the end of the line for Wayland/Weston 1.0.x.
There isn't any major pieces of the puzzle missing for the stable Wayland/Weston 1.0.x series so it's now time to focus upon the next major release and introducing new features. The odd numbers (i.e. Wayland v1.1) are being reserved for development versions so the next major release will be Wayland/Weston 1.2.
Among the plans expressed by Høgsberg include merging the IM + OSK work, splitting out XWM as a client, remote rendering functionality, and sub-surface / surface group support. Those are the items that are on Kristian's mind right now, but more features are likely to surface before the Wayland/Weston 1.2 release later in 2013.
The initial Wayland 1.2 details were shared in the 1.0.3 release announcement.