Talking about the map and quests, not high level contents.
There is zero flexibility, despite being an open world game. You must do X first in order to reach Y or open door Z or go through certain route. It's not just doors, but also unpassable low mountain edges or fences that a normal kid would just jump over or climb easily (just lift the god damned feet!), and when we fall to water we can't just climb from any edge with hands.
What's the point of such restrictions? There are games without those arbitrary limits and their environments are super fun to explore! Imagine you can just climb mountains in Coldharbour. No stucking between stones or following roads all the time, and ZOS can add a lot more contents on existing maps.