Also, there's a big difference between "Characters who are starting a new story arc will go to a place they haven't been before" and "The climax of a story will suddenly shift location to a place with no obvious dramatic significance." Usually, when the Oots goes to a place as part of an adventure, they finish the adventure there before leaving. But I doubt that anyone would have argued it was unlikely for the Order to go to anywhere in particular as part of a side adventure between gates.
The better analogy here would be "Before it turned out that all of Girard's descendants were dead there was no plot-relevant reason to move the climax of the story arc to the Empire of Tears... and so they didn't."