I'm assuming the reduced mobile functionality is b/c of the changes/gutting occurring on desktop where she's become a disjointed, and mostly useless, mess.  The mobile stuff stopped working pretty much at the same time 1903 became publically available.  Given she's a service, it makes sense the changes to separate her from search and further reduce her "app" abilities are now trickling down to mobile.  By the time MS rebuilds her as a pervasive AI assistant, W10M will be long gone.