Years back, I wanted a new type of system UI primitive that was like a widget, but for transient events, to track your food order or count down to a bus or train. More information is still forthcoming about Live Activities, but given the examples were an ongoing sports match and the status of an incoming ride, I am optimistic.
Heavens to Betsy, apps can themselves have extensions now with ExtensionKit. There's even ExtensionFoundation for non-UI extensions.
There are now extensions for streaming media to "third-party" devices within the AirPlay menu.
There are also App Intents with the ability to pass data in and recieve data out on the other side, along with optionally showing UI. Siri and Shortcuts so far, and being able to be triggered via widgets, but tell me if this doesn't sound like macOS Services and wouldn't be ideal to be triggerable via context menus on selections.
There's also an iOS 16 "Developer Mode" device opt-in.
All of this is good stuff. The platform becomes more of a platform – things talking to each other, developers becoming more powerful and the user being in control. In many of the changes, it is impossible to conclusively separate whether they thought it was a good idea that needed to happen or whether they just didn't want to build it under the gun. (I will note that they have been and remained good ideas for numerous years.)
And as for a gun, well, having a Developer Mode that "lowers security" would put them in alignment with Android if one day they lifted the restrictions to allow broader distribution without going through orifices.