I don’t really get this criticism. Max is important to the plot and the themes. It’s his idea to go back to the Citadel. When Furiosa loses all hope, he’s the one who picks her back up. It seems like a small moment but it’s key to who he is: He lets himself be part of the group, instead of the loner if only for a brief moment - long enough to save Furiosa’s life by giving her a transfusion (being a bloodbag!) and finally telling her his name, his one sign of trust. The movie very much has a Western quality to it, and I think you can liken it to something like a Few Dollars More, another movie where the hero takes a back seat while the secondary hero takes his revenge on the movie’s main villain.
