I have an idea how to solve this.
Track all applications sending notifications and dynamically add them to Manager list allowing user to disable pushing from specific (already seen) application. This way it does not need constant updates to the app code adding new notification sources and gives total control to the user.

But this needs coding it up.
And I have some other tasks with higher priority.

But smurfy is working on something like this, so he's the one to bug for.