Since playing Daggerfall, there have always been secret passages in dungeons that don't appear on the map. Things you had to explore to find.
Likewise, ESO has a lot of ladders... That the player can't climb.
I'm no game designer, however would love to see Zenimax continue providing interesting reasons for players to explore this amazingly detailed world they have created in ESO.
So many buildings, caves and dungeons have an incredible amount of detail in them, but why bother looking up if you know there's no chance there will be anything there?
Why go exploring the nooks and cranny's of a dungeon if likewise, you know there's no chance there will be anything there bar an urn with a scrap of Horker meat?