I think there is something to be said for the illusion of scale. Things taking a while to traverse make things feel huge. You can already feel the difference right now between when you first enter a zone and when you get flying. Airships and boats requiring 5-20 mins to reach their destination would show that "yes. This world is big". Considering we can already teleport so easily, I wouldnt be opposed to having slower methods of travel actually have travel time. Right now we can go to the edge of the universe, and honestly it doesnt feel that far away at all.