The herb/ore farming came into focus recently because of Nazjatar being the only place to get the new herbs. There is little reason to go to these zones anymore unless you are working on getting flying (which is a much lower amount of players) or you are gathering the nodes. So the entire zone is now just gatherers and it exasperates the problem. A multiboxer has no effect vs a solo player on this unless the boxer is playing 10 (which is also not as common since you'd have to split to 2 bnet accounts).
The hyperspawn farming I'm assuming wasn't an intended method for farming but it has been ongoing for more than 1 expansion now. I actually even saw this on Classic.


More to Shadowlands and while I am hyped for Shamans being a potential option coming up. They are still a very turret like class and WoW has evolved so much mechanically that if a lot of bosses or events require movement Hunters will still reign.