I thought I read somewhere that they were re-implimenting some of these removed recipes? Are any of the 21 you mentioned on this list? or are the 21 referring to ones that still aren’t coming back, even with this list?
Community Compilation of Returning Items Previously Removed with Cataclysm
These 21 are not included in that return of items 
There are 38 vanilla recipes that still exist in game that are as of today unobtainable,
21 from quests
9 trainer recipes
3 world drops
3 dungeon drops (all UBRS)
2 vendor
outside of my own hopes as quests are my focus, more and more things are being added back, but we havent gotten any quests back
its hard to get exact numbers but easily over half of whats still unobtainable from vanilla is either a quest or quest reward
Thanks for the list! I agree it would be great if a lot of these could be put back into the game, maybe through interactive stuff like we’re getting with scholomance/nax right now. I would love to see that. I think that for all the amazing stuff Dragonflight gave us, the old scholo + questline and the questline in Nax to get Valiance and T3 crafting was the best and most loved thing for me. I feel like they could easily address this with something like phasing/Chromie time to let us “go back in time” and get those quests and drops. 
This thread hasnt been poked in awhile pokes
Positive Progress since the last post:
not to much has happened on this front, but the promotional rewards has gotten a bit better with the trading post
Some back tracking:
We have also had some back tracking as well unfortunately, mainly the primary questchains of Love is in the air and Hallows end, both of these chains had been partly broken for years and with the announcement of holiday updates, we had hoped to finally see them fixed, but unfortunately they were competely disabled instead 
The new chains added in their place are very good, but there really wasn’t a need to disable the original ones