Feature overview
Option to view related posts as a tree.
Examples
parent
-child
--grandchild
--grandchild
-child
or
parent
child child
grandchild grandchild
Ideal location would be in place of the current parent/child links or on a separate page altogether, like pools. If the former, highlight the current post in some way.
Usefulness
Many child posts will have their own child posts. A blacklisted parent may have unblacklisted child posts. Being able to just click a post further in a daisy chain removes the need to open a preceding post first.
Affected
1) Every post with a parent or child(ren) or 2) an entirely new page. Since it's an option, the settings page would also need an update in the former scenario.
Edit: Tried to show a family tree using nodes for the second example. I don't care enough right now to find out how to make it display correctly.