I can see them removing the rep requirements after BfA is done, but I'm not sure about even that. I think Blizz is getting tired of making content that nobody ever uses ever again, especially when the content is as grandiose as the Suramar storyline and Argus. The stuff is well made and reignites a lot of that old spark for the game, it seems natural to want new players to experience it to unlock certain rewards.
Also, funny side note, people get really butthurt about having to go back and do old content or a friend starting into WoW having to do the old content, but then argue profusely about the necessity of having classic servers where you are limited to old content.