Need ability to view all subtasks assigned to me that are ready to be worked.
If they’re assigned to you, they should all be in your My Tasks view.
How do we add dependencies between subtasks?
Click the parent task to open its detail pane on the right-hand side. Then find the subtask you want to set as a dependent and click its “Notes and comments” icon all the way on the right side of its row. That will open the subtask in the detail pane and you can then set it as dependent just as you would any task (using the three-dots menu, then “Make dependent”). Note: There are also keyboard shortcuts for all of the above actions.
Is there an automatic notification that sub task is ready to be worked once predecessor has been marked complete?
I believe notification on dependent subtasks should work the same as top-level tasks. (I haven’t tested this to verify it, though.)
Is there a way to create and customize reports to my specific needs?
I think your best bet for customized reporting is @lpb’s excellent Asana2Go.
Is there a way to view all open projects and their associated subtasks and subsubtasks all at once, without having to click and click each one?
Not in Asana itself, but I believe Asana2Go can give you a view like that.
In the List view, is there a way to expand all with one click?
Not currently. It’s a popular request here in the forum, though, and you can add your vote for it here: