Atlassian seems to have not allowed comments on any of the articles about this change, so I'm starting this discussion thread!
I am failing to see how removing parent links above the Epic level is a positive change. We all know projects long ago grew in most organizations to need more hierarchy than just Epic/Story, and this will now remove our ability to add in our own hierarchies and tracking in a way that's easily traceable.
This in my case breaks all our reporting, and also all my automation around Epics and their parent ticket type (since using "relates to" is NOT a solution that I can rely on for automation rules.)
I am strongly against this change, and I cannot be the only one.