Re-organizing multiple tasks by using the outdent, indent, move up and move down is slow and cumbersome. It would be a lot easier of we could simply drag them into their new position as can be done in MS Project.
This exists already.
To drag and drop tasks:
select the tasks to be moved
left click and hold in the line numbers area of the Task list
move the cursor to the line number where you want to insert the tasks below until you see the cursor change. there are two icons - one to move tasks below and the other to move the tasks to be child tasks of the above task
release the mouse to move the tasks