One thing that stood out to me was the lack of attendance of a representative of the Imperial household at day 1 (or any day) of the Aki basho. Typically the Emperor or the Crown Prince will attend a portion of day 1 of any basho held in the Kokugikan. To my knowledge, this was not the case for Aki. During May’s Natsu Basho, the duty went to Crown Prince Naruhito, who was warmly received by the crowd. Emperor Hirohito (Showa) was a massive sumo fan, and would regularly attend.
Much of this is likely due to the declining health of the current monarch, Emperor Akihito, who will likely abdicate the throne in favor of the Crown Prince, quite possibly at the end of 2018. While purely ceremonial, the presence of the Imperial Household at sumo and other public events is a foundation element of Japanese cultural and civic life.