Summary: Simple (user-initiated) creation of a dedicated desktop shortcut that opens a single app within a steamlined (UI-free) window, thus creating a native-app-like experience for end-users.
Here's the dream; A button within the PowerApps interface (or a link sent directly to the user) allows them to "Download" the app. This action would create a desktop icon (matching the custom icon of the PowerApp), that when clicked, would open the app in a dedicated window (either a native Win10 exe frame or streamlined browser instance) that then simply loads the app with no other UI elements, including the PowerApps header/navigation bar.
The current solution of loading the app through the PowerApps Windows 10 desktop application requires too many hoops to jump through (i.e., download the app from the store, open the host application, find the specific app you're looking for) and puts the application out of site/out of mind for users. Giving end-users the ability to interact with a PowerApp as if it were a native desktop application would remove significant obsticals and dramatically increase the adoption rate of new tools.
The closest we can come now (as far as I know) is using a browser like Google Chrome to "Add to desktop" which basically saves a shortcut with a generic icon to the desktop that opens the URL in a streamlined browser window as if it were a desktop application. This is fine for one-off use, but it's clunky at best and not at all ideal for broad deployment.