Is there any particular reason the politics of the North and Vale are shorter than the other Politics of the Seven Kingdoms essays, or did the essays just grow progressively longer as you got into the habit of writing them?

Mostly the latter (I really didn’t think any of these essays were going to be multi-part), but as I state in the essays, a lot of it has to do with how much material there is and isn’t – both in the North and in the Vale, we have long, long multi-thousand-year periods where we don’t have anything to work with.