I remember to have high hopes in Vala when discovering it. But never actually felt the need to learn or use it for real.
Which tells a story.
Which tells a story.
What's also interesting is that in Gnome 3, which came just a few years after, they chose JS because so many people already knew it and could easily develop for it.
I'd say the latter was the better idea, as there are far more shell extensions than Vala applications.
Likewise, I used to write Windows software in Pascal with parts in C and C++ because I oddly both found Win32 and COM and found interfacing with third-party libraries easier to deal with that way.
I'd point to PyQT as an example. It's function and documentation are flawless. I was able to build an entire web browser using it in a day(no, not a chrome competitor, just a simple one using QT and webkit components). The 'official' libraries are so clumsy in comparison.