I am an excessive XWiki user for years, but just today I created my first App with App Within Minutes. And it is a really cool possibility for structuring knowledge artifacts.
I don't know if the AWM is too less propagated to the users. What if AWM is integrated in the 'Create Space' menu to reach more users? So when you create a new space, first a dialoge asks you if you want to create a regular space, containing pages editable with text editors, or if you want to create an app space ( or structured space or some other wording) containing predefined knowledge artifacts.
But maybe I am wrong and this would make XWiki more complicated. But on the other hand how often do you create a new space? I think there it is a nice offer creating apps.