The big picture issue here is the forced link between the WAB developer edition and the named user model. Secondly - being forced to use web maps instead of ArcGIS server Rest services for WAB basemaps.
I can see the need for application registration if one chooses to deploy one's app in AGOL but why does esri force all customers/developers down this road? These should be optional steps than requirements.My org is an esri customer and we pay for both ArcGIS Server and AGOL but are really frustrated with the some of the unnecessary technical restrictions around being forced into using named-users and AGOL web maps.
I say this here because the folks who responded here have been building web applications from the Flex era and before and might appreciate the loss of developer and customer freedom more than others just joining in.
Thanks,
Subu