Open source projects live and die on their community, which springs from examples and documentation that people can learn from. I like the look of Ionic, especially if it was decoupled from Angular, but until it's possible to actually do something with it I (and I imagine many others) can't help out with it.
tl;dr Documentation is critical. Write some, don't just rely on your "doc generator".
The community has actually been more active than we expected, and the forum is seeing a lot of activity in the last week: http://forum.ionicframework.com/
The homepage look very nice but I had pretty much the same issues as you. ---
Frankly I built my own UI because I didn't like the opaque layer most mobile web framework are doing (exception being jQtouch but it's pretty old). It's not "that hard".
It's also bound to angular out of the box. While that's great for people using that framework, it's a big learning curve for anyone else.
When it comes to the overwhelming number of mobile js frameworks its hard to get an idea of speed without running each of the demos individually and comparing. Do you have any rough stats compared to Sencha?