I worked most of the December time on gtk-doc. After more that a year I released 1.12 and 1.13 on the same day:). Most notable features are probably that now one can have syntax highlighted and xreffed examples and the generated indexes have a prefix detection. That means the index has proper a,b,c sections and not everything under 'g' for for gnome libraries. The best thing - you don't need to do anything, just update your gtk-doc version. Now I hope that someone kindly installs 'highlight' (or 'gnu-highlight') on the server that runs library.gnome.org (or do we need them on build.gnome.org?) so that we get the highlighted docs there too.
Now if you want to do something, have a look at these two commits and do the same in your package. It helps maintenance and it builds faster. If you want even more speedups go for gtk-doc from git head. I managed to tweak the xslt to save a third of build time. I mostly replaced some templates to avoid i18n which the api-docs don't use anyway, but also cached some nodesets.
On buzztard I also spent a little time, improving the docs and pushing the test coverage further. I will attack the bullets on the 0.6 roadmap next. Happy new year and stay tuned.