Question

It would be really convenient if for certain tasks in org-mode, the subtasks could inherit the deadline of the main task. This behavior should occur in case I have not already specified a deadline for the subtask. In this way, all the subtasks would show up in my org-agenda view, with proper deadlines which are easily manipulatable.

Answer 1

How about a function for adding subtasks? This one adds a deadline to the subtask if its parent has one:

(defun my-org-insert-sub-task ()
  (interactive)
  (let ((parent-deadline (org-get-deadline-time nil)))
    (org-goto-sibling)
    (org-insert-todo-subheading t)
    (when parent-deadline
      (org-deadline nil parent-deadline))))

Don’t forget to bind it to a key:

(define-key org-mode-map (kbd "C-c s") 'my-org-insert-sub-task)

Also you might find these settings useful:

(setq org-enforce-todo-dependencies t)
(setq org-agenda-dim-blocked-tasks 'invisible)