Mad Max 1 wasn't even a post apocalyptic movie. The director didn't have a lot of money so they just did some thing about a guy surviving gangs. He was surprised when he heard people uniformly fill in the blanks that it was post apocalyptic. Anyway, it isn't that great... but it isn't bad either. There is basically no plot period.
Mad Max 1 wasn't "post-apocalyptic" but I think it was more interesting than that -- it was *pre* apocalyptic. It was set in an era of severe social and economic decline. Petroleum was becoming very scarce. Government services were basically in tatters, law enforcement was marginal at best -- they had basically lost control of the countryside and rural areas -- there was basically no law enforcement in the small town where the biker gang picked up the Nightrider's coffin and terrorized the townspeople.
And of all four of the films, it has the most plot and narrative. It's characters were much more representative of real people and situations. It's true the social breakdown/decline weren't well fleshed out, though.
IMHO, this setting is actually more interesting than the post-apocalyptic wasteland of the Road Warrior. Road Warrior was a fun film, but it was really nothing more than an action film with an S&M wardrobe that recycled the character and car from Mad Max but made no coherent effort to conceptually link the two films.
I haven't seen Thunderdome in years, but in retrospect it was kind of a joke although I seem to remember being entertained by it. Fury Road was basically a reboot of Road Warrior -- highly enjoyable, but other than a name and a leather jacket it really had no connection with the other films.
Personally, I'd like to see a prequel to Mad Max 1 that traces the origin of the MFP, the rise of Max Rockatansky and does more to flesh out the decline of civilization. I think that setting is more interesting than the bizarre mythos of The Humongous from Road Warrior or the cartoon world of Fury Road.
There was a recent film with Guy Pearce called "The Rover" which was set in a modern, post-economic collapse Australia that would serve as a good inspiration for a Mad Max prequel. I think Guy Pearce would make a good Max Rockatansky, too.