i agree legend that fast travel is a band aid for poor world design.Yeah, large empty open world's are bad.
i also agree with Pi that travel can be tedious if all you want to do is travel to a place and it takes 10 minutes to get there even with a mount.
i generally disagree with large open world being a good thing. smaller but denser with a good focus on exploration/discovery is better to me.
Density is more important than size i think. A small dense open world is better than a large empty one.
Walking 15 minutes with nothing to note just makes it tedious.
I personally like large open world's as long as they have the density to make it feel like there's a reason to be that large.