Siri has been getting better ever since its release. Have you used it in iOS 10? It now has 3rd party integration with Uber and Lyft, Venmo, and many other apps. Its reliability and usability have drastically improved since Siri 1.0 on the iPhone 4S.
And yet, the simplest interactions always disappoint me. I said "Create an appointment with John Smith at 2PM tomorrow". John Smith being someone who isn't in my contacts. Siri presented me with a list of my contacts that she thought I might have meant. The option "None of these" was also presented. I chose that, thinking she would just create the appointment with John Smith in the title as plain text like I wanted, and she said "All right, I'll leave it off your calendar" and that was that.
No integration with the apps i care about: spotify, google maps, gmail and many others.
Isn't that on Spotify and Google to implement?
You have a whitelist of possible domains though (Messaging and payments being the most common for now)