Did no one else watch?
The documentary gave me a renewed appreciation for Hakuho in terms of his entire body of work. A reminder that he wasn't always the dirty-fighting Yokozuna that we became accustomed to toward the end of his career.
That he shouldered the burden of the scandals that rocked the sumo world and almost single-handedly kept the sport alive through his dominance--to that end Kitanofuji, interviewed for the documentary, commented that sumo might not have survived had Hakuho not been there to keep it together.
That it was he who was instrumental and doing support activities for the victims of the Fukushima earthquake and tsunami, and continued to donate both his time and money in the ensuing years.
He talked about wanting to be loved by the Japanese sumo fans, wanting to model himself after Taiho and Futabayama. Yet as he continued to dominate, blasting through Taiho's record, and then repeatedly foiling Kisenosato's bids for yusho and promotion to Yokozuna, Japanese fans instead looked at him as the heel--to the point where he eventually embraced the role.
He said that he had decided that Nagoya was to be his last basho even before it started, and wanted to go out like Takanohana had when he toppled Musashimaru for his final yusho. His knee was in terrible shape throughout, and he received constant therapy during the basho.
Regarding the Shodai tachiai fiasco, he said that the night before the bout he tried to visualize beating Shodai, but could only see himself losing at tachiai, so his only recourse was to avoid it by moving back. Clearly at this point he was in desperate win-at-all-costs mode. And when he finally did, his victory shout after toppling Terunofuji was the joy and relief at having achieved his final goal.
Just prior to mounting the dohyo for the final bout of his career, he could be seen in the video footage giving thanks to the dohyo for what sumo had given him.
He was asked what hinkaku, and by extension, Yokozuna-sumo, meant to him. He replied that whether young or old, or no matter how kind you may be, as a Yokozuna it was either win or retire. So for him it meant being a devil in the dohyo and kindhearted outside of it--and winning at all costs.
Kitanofuji and Araiso were also asked about hinkaku--for which there is no specific definition--and neither were able to give a clear answer as to what it means.
He closed by remarking that he loved sumo more than anyone.
That's all I remember off the top of my head. Feel free to add or correct whatever might be missing or wrong.