I miss in Todo to have a list of a project's subtasks different than a list of the project itself.
For instance, a project Book is in list Projects and it has subtask "Author - To deliver text".
By now, Todo doesn't allow to assign a subtask to a different list than its parent task. The list is just inherited from the parent task - it is Projects in this example.
To have Todo more useful I suggest to have possibility to assign the subtask "Author - To deliver text" to list "Waiting for". Then I can have all subtasks of a project together but I can track what I am waiting for at the same time.