There was a time back in ARR when dungeons could be scary.
People had to utilize strats like [Sleep] and other crowd control spells to "reduce" the amount of "active" enemies you were fighting since you could be overrun and die.
Pulling more packs of mobs than 2 often spelled certain death.
Heck, if your group wasn't experienced even 2 packs of mobs could spell disaster.
Edit:
Dungeons also had a couple of "wandering packs", meaning that enemies walked in (set) paths back and forth.
So if you weren't careful you could get ambushed while already fighting another pack, which often lead to a group wipe.
I miss those days honestly.
But I also understand that in the modern era of MMO's people don't want to spend longer than needed in dungeons (and other duties).
But it did make the game feel more engaging and rewarding when you beat the content with others, imo.
There were dungeons that had diverging paths as well.
But they were simplified into a single pathway since people only used the most optimized paths anyways.