While doing the secret stuff for the Fel bike on my Shaman who had not seen action since Legion prior to TWW, I definitely ended up spending a lot of hours figuring out what I needed to do again to unlock access to various zones/phases on my Shaman specifically 8.3 Vale was the big time killer.
I had of course done these before on other characters when the content was current so it was not the first time.
How many raid tiers would it cost to add some more “I have been there and done that already” dialogue options for main quest gated content of the past?