I'm glad they both exist.
The open world is used for very different purposes. In The Witcher 3 I've found that it's open world is basically meaningless - it's just empty space that forces the player to engage in boring traversal between dialog scenes or combat sequences. Moving across the world just isn't fun. It's poorly animated and there is no challenge or gameplay element there. You just push the analog stick (or hold "W") in the direction you want to go while only occasionally stopping to fight an enemy or start a dialog sequence. It feels like wasted space to me and it has kept me from enjoying the game as much as The Witcher 2. How does it allow you to approach things in different ways exactly?
Batman's open world isn't designed to be an NPC quest dispenser - it's a playground which is organically connected to each main stage. Driving or flying through the city is, in itself, an enjoyable action. It's fun to navigate the city. The city is also integrated into the main missions rather well. The game is full of variety and constantly shifts things up in a lot of very creative ways.
With The Witcher 3 you're either triggering a dialog sequence or engaging in combat. The open world is a barrier to the content (at least for me).
It's not just The Withcer 3 either - I have this same issue with most open world games these days. Games which just place a bunch of NPC mission dispensers around the map while lacking anything in the form of interesting traversal. You're just crossing empty space on the way to the next cutscene or combat section. The worlds often feel meaningless - big for the sake of being big.
