Not a clue mate, I also wonder why versions of the library up to 1.12.0 are available for download on OSS (see Notes 1747308 +1851843). And yet on developers.sap.com the latest available version is 1.8.4.
I would think releasing the library early to developers and asking them for feedback is the correct strategy. Can only think that developers are wasting time developing features and workarounds for features that are already productive.
" App Designer .. I think that is mainly focused on Mobile Apps right?" good question, for me an IDE based WYSIWYG view editor is more preferable to an App Designer
Cheers
JSP