She should have been. Tom Hardy's character should have been the feral child from the second movie. (Teased in the movie, but denied by the filmmakers.) And Furiosa should've been the star.
Why?
And she is the main character. She's the main focus of the movie. It's more her story than Max's. Max is the vehicle of the story and we follow him, but he's not what the movie is about really. It's Furiosa's story.
It's like The Road Warrior. The movie is about the gas town people escaping Lord Humongous and his gang. Max is just along for the ride pretty much.
He's in the movie's title. He's credited before she is. He wins the fight the two of them have. The camera follows him when she's off-screen. She does kill the the main villain, but Max has a history of not being the one to directly do-in the bad guy. He may be the "vehicle" for the movie, but calling Furiosa the star of the movie is like saying that the Scarecrow is the star of Wizard of Oz.