It's been a little of both - I can get a custom widget to display including with a dijit combobox now, as long as I'm not trying to also load the jquery library in the declare statement:
'jimu/loaderplugins/jquery-loader!https://code.jquery.com/jquery-git1.min.js',
This I find strange because the same line works fine in the UseJQuery sample widget.
Yesterday, I tried to put your Identify (copied in the whole directory) in the directory:
C:\arcgis-web-appbuilder-1.2\client\stemapp\widgets\samplewidgets
The identify icon then comes up in the webappviewer toolbar as expected, but will not execute. The only message the displays is a popup that says "Create widget error: Widgets\samplewidgets\Identify\Widget"
I'm continuing to wade through all this, but just wanted to see if that was something that had come up in the past. I'm guessing just I have some configuration item set incorrectly, as all the tutorials appear to make it fairly easy to build custom stuff.