

Lots of the vanilla WoW instances was like that. Often the way to the entrance was populated by the same level elites as the dungeon so you had to run a gauntlet just to get in.
The Deadmines and Uldaman comes to mind. And since you spawned at the entrance you had to dodge and sneak past patrols avoided on the run. Gnomereagan and Maraudon and parts of Dire Maul was very maze like if my memory serves me right
Forgot about BRD. I also remember stranding in Ironforge begging for someone with the key to Upper Blackrock Spire to unlock it. Man that key was hard to get, and the gems did not even have a 100% droprate