So many great points. I'm very happy to hear that someone is thinking of the UX. I only wished they worked on Siri.
The only addition I can think of is during the wake word section. I'd like to remove the wake word requirement if I'm in the middle of an interaction.
For example, sending a text on Siri.
"Hey Siri text my wife. Tell her I'm on my way"
Siri shows me the text and then I have to again say "Hey Siri send it" when just "Send it" should do.