Mary Jabassa was the best character in the film

Agreed, that would have been a much better premise. The movie peaked in those first 20 minutes. It was downhill from there.

Interestingly enough, Mr. Norton (the disfigured woman riding with Dementius) is played by Hemsworth's wife (Elsa Pataky) who also plays the vuvavilini soldier who bids farewell to Furiosa's mother at the beginning.

Can't help but wonder if they're in fact meant to be the same character, years later, after the destruction of the land of abundance and torture of their dwellers, who might have gone mad and decided to join dementius.

But see, that's precisely why I disagree with the opinion that not enough is shown or explained about some charachters: I love that Miller just lifts the veil high enough for us to catch a glimpse of the possible history/fate of characters, the history of the world or the relationship dynamics between character. it lets the imagination run wild and doesn't follow the prosaic structure of pausing the film for exposition. It's a rich, fully dwelled-in world with its own culture, language and history, and although you're not meant to understand it all, you don't need to and you still get a sense of its richness.

It bugged me that we had this whole big scene that introduced Mr. Norton, but it was mostly for nothing. Besides I guess just to show how crazy Dementus is and how he recruits his gang members. The whole movie is filled with random scenes like this. Here's a thing that happened, here's a new character in the story, anyhow, moving on. Over and over.

Octoboss is cool. We see him get upset with Dementus over how his men are used. When next seen we get a throw away line of dialog about how he's split away from the group. Though it makes little difference to events unfolding. Which leads to later evidence of strife on Team Dementus. It's like all the story in this movie happens off screen and you have to figure it out yourself. I don't know if this is a bad thing. It's just a real weird way to make an "epic" movie.