Subtasks are great, but using them with lists and smart lists isn't. Today, subtasks only show up in a list or smart list when their parent task isn't there. Which is a sensible default, but not always what I desire and I suspect other uses may feel the same way: I sometimes would like a view where I see everything I have to do, in which case seeing the subtasks is crucial to getting that flat view.

So lists and smart lists should have a new option about their subtask behavior. It should have the following options
* always display subtasks
* (current default) include matched subtasks whose parent task isn't matched, which could perhaps be called "summarize"
* never display subtasks