This seems very powerful. The open-ended approach of letting apps expose their actions and letting the user choose which they’d like to use and how they’d like to phrase their Siri requests isn’t what I expected, but I think it might be a great solution. It seems like a big step forward from slowly adding 2-3 specific Siri domains per year as they’ve done in the past, and involving the user in setting up the Siri query seems necessary since you can’t just let apps start adding their own voice commands to Siri ad-hoc, it would be impossible to manage.
The ‘Shortcuts’ workflow app does seem very power-user centric, but the way they showed typical everyday apps presenting the user with an option of adding a Siri action seemed very reasonable and simple . . .