If hearthstone will become soo big. it should be the other way around! hearthstone cards COULD become inspiration to wow lore!
It's not as if wow lore is a closed book.
Which it has on multiple occasions as of now with Sir Finley and an example during Legion. The Tortollans are another example in the upcoming expansion Battle for Azeroth , along with Sky Captain Kragg and Patches which are dungeon bosses. Hell The OP of this thread is even wrong about how there are no legendaries that are from WoW because Subject 9 is a quest giver in Azshara if i remember right