@Flohack Did you mean this?
It's just an early exploration done through a QML mockup, the UX design is currently the same used for scopes.
Conceptually, it should work as a JSON documents aggregator. Apps would be able to update their data in background, using the new account-polld service, or during app execution, and the homescreen would fetch those new data once they become available.
This way the homescreen would work like a sort of Google Now clone, without sending user's infos here and there. Everything relies on the availability of those data locally.
What it would get lost is the ability to perform per-scope and remote searches, however it would enforce a proper model where advanced features are provided by apps only. In any case, we could add a search bar in a different tab in order to allow online searches via Google, DuckDuckGo, etc. anytime.
This would be available for all the third party apps that'd like to use it, with the only limitation that their "homescreen widget" could expire if their data are not up-to-date.
A few integration cases I will probably take in account are: Apps, Events, Weather, News (e.g. Morning Digest, Afternoon Edition), Bookmarks, Contacts, Documents, Books, IM apps (e.g. for latest conversations list), Notes/Tasks, World Clock and Spotify playlists.
Of course, this is just an idea that hasn't been validated yet. Nothing has been decided yet.