Problem: Convert to Task/Subtask are kind of a hassle, especially when I want to make a simple change within the list I'm in.
Solution: Enable us to drag or snap in or out to signify a task or Subtask (Workflowy does an amazing job of this).
It would be easier than having to type a task, then click the add Subtask button, then add the Subtasks, then repeat. I could simply type a task, type the next one, drag it in and the ones to follow would automatically be subtasks as well (until dragged back out).
Problem: Subtasks can't easily be repositioned to go under another list item.
Solution: Make Subtasks completely draggable as tasks are.