Rare farming can be done a lot better. WoW has lots of problems in this regard, as far as having it be a fun and usable system.
Take an example of a game with much more developed and advanced rare farming: Guild Wars 2
Just some details they do better:
There is always an appropriate amount of world instances for the number of people online. When populations are low, instances close, and people in closing instances are given a warning of the shutdown time and a small karma booster for swapping to an active instance voluntarily.
The group finder has more specific interest sections, laid out in a more usable way. Group leaders get an icon on the zone map so people are able to see where groups are. People can join groups in their instance by clicking on the group leader on the map.
Rares have specific spawning schedules that you can see in a table on the wiki, so instead of flying around chasing random spawns, group leaders can direct people around in a sensible way. What WoW calls rares, GW2 calls world bosses. What WoW calls world bosses, GW2 spawns with a fairly long and intricate event chain before hand that are quite a lot like WoW’s new siege event. WoW’s siege event just spawns a crappy low grade rare, though. It’s not very sensible to have a big event chain before killing a soloable rock.
WoW seems to like to have clunk and jank in the worst places to have clunk and jank. The hardest thing for people to master in an MMO is dealing with other people. Like 80% of WoW’s jank is amassed in the grouping and instance systems. This is where MMO devs should hyper focus on not having chronic major issues. This is the only place WoW seems to have chronic major issues. Someone’s not thinking straight at Blizz on this issue. I think WoW’s biggest issue overall is the guild finder, it’s the same thinking that make’s WoW’s group finder junk. How are people supposed to find “like minded players” when the guild finder options are PVE or PVP? No one at Blizz thinks there’s a little more nuance to human thought than that? Come of it, my dudes, there’s something going wrong there.