It would be great if it was possible to create a task (using the "smart add" feature) directly from iOS's home screen, by "3D-touching" the application icon. This would open the "smart add" window and allow the user to quickly create a task.

3D-touch is this iOS feature:
https://developer.apple.com/ios/3d-touch/

In the attached file, as an example, the 3D-touch menu for the standard iOS "Notes" application on an iPhone 6S is provided. (In it you can see the "New Note" menu item, which is similar in functionality to this feature suggestion.)