Especially with Shortcuts, Siri can have some pretty useful functionality. My personal big improvement I'd like to see is being able to better able to tap into those actions without having to set things up in advance.
A year or so ago I remember someone pointing out in a podcast how LLMs are great at taking something like general language and turning it into a series of predefined commands (the stuff available to shortcuts). It would instantly make Siri much more useful.
I think Federico Viticci rigged up something similar or at least a powerful demo using Siri + Shortcuts + ChatGPT to be able to answer all sort of questions better than native Siri.