For example you set out in Dun Morogh at level 8. The boars and cats feel daunting, even pulling just 2 at a time might kill you.
But you grind it out and at level 30 you’re ready to hit a Gnomer. You gather all the quests and run to the dungeon, which forces you to run through the entirety of that zone you were in days or weeks ago. Those same mobs that were so challenging are now laughable. The difference demonstrates how much your character has grown stronger. Look how far you’ve come.
There are lots of quests and dungeons like this, that force you to run through previously cleared zones to get somewhere new. And it’s this constant retracing and criss crossing that makes the game feel so amazing to play.
On top of that this creates intersecting paths for high and low level characters. You’re grinding at level 35 and a level 50 runs past you on their mount. It motivates you to grind on.
In Retail this doesn’t happen. You clear a zone and you never see it again. You get new gear but all that means is you can from Mythic + 4 to M+7. The game fails to make it feel like the progress you’ve put so much time and effort in to is meaningful.