966 was fairly lacklustre for the importance it was supposed to have. We see Roger and Whitebeard imbuing their weapons with Busoshoku Haki. Gee, I wonder why Whitebeard never used this at Marineford if Oda's supposed to plan everything
Oden's becoming a bit too much of a self-insert now. Yes, we knew beforehand he'd travelled with Roger and Whitebeard, though him being at the centre of most of the key events known of the Roger Pirates' journey to Raftel and being so integral to it when the crew was supposed to be able to understand what the Poneglyphs said through "hearing their voice" makes it pretty obvious how big of an attempt Oda's making to retcon Oden into key events. At least it was explained more people could decipher poneglyphs if the World Government didn't ban doing so, making Ohara being the last civilisation to do so rather than the only one; of which the latter would've had no explanation for this exclusive trait.
We learnt Blackbeard's supposedly never slept in his life, likely due to whatever unique mutation allows him to have 2 Devil Fruits. Not much of a reveal beyond hyping up how special he is.
Overall, an average at best chapter, though it at least provided interest in the one to succeed it and is still better than any of the events in the current part of the chronology.