There are a few things about Things that drive me a bit nuts. All of what I am talking about is possible to do through shortcuts, but that isn’t something you can integrate into widgets etc.
A big thing I hate is how it isn’t possible to have saved searches in the side bar. For example, I’d love to have the “tomorrow” list always there.
But in general, in a shortcut you can do rather complex queries, sort them in interesting ways etc and show it as a search in the app. Like only show me todos or only show me projects.
It isn’t that well integrated with the rest of the system though.
The same thing kind of goes for the Headings you can add to projects. They’re kind of invisible outside of the project view.