There is another option, and it's that while "Winterfell" was a bit milquetoast, the rest of the episode titles are a bit more revealing — too revealing for fans to see lest they get the ending to one of the most zeitgeisty shows in the world totally spoiled. To prevent such spoilage, maybe HBO will continue to release the names after the episodes air, so there's no chance of any of the fans getting too ahead of the curve.