To see how much of a jump he made over ten years, consider Lorenzo's Oil - it's basically a two and a half hour movie full of just people talking, arguing, considering, and running back and forth in a house, but it feels just as masterful, kinetic, and relentlessly involving, as the Mad Max films, purely because of his greater control of the image, and mise en scene. To be fair, Miller hates the first Mad Max too, because it is very clear that, while ambitious, this is someone's first film - as someone else mentioned, there are sequences where it's very obvious that Miller had to find time to fill the air after running out of money for another big set-piece, and the film's dialogue can occasionally be a little awkward, in that way where it sounds great on the page but not so good coming out of people's mouths (like Max's monologue to Jesse about his father's boots) - George Lucas had this problem and never lost it, but Miller got better, deciding to emphasize the use of silence and visual storytelling in his filmmaking style. It's a trademark Miller narrative, although a little shakey and unsure of itself considering it was his first film that he'd either written or directed and a lot of what he'd had planned had to be cut out due to a tight budget: the film builds and builds and builds throughout its first half, consequence on top of consequence, letting the pieces fall into place until the main character is forced to make a sudden, inescapable decision that propels him through the last.say, forty-five minutes (or in this case, an exxagerated fifteen minutes) at a single-minded, relentlessly breakneck pace.
It's also notable for its spare, minimalist set design which suggests in broad strokes the slow downfall of society in a way that hadn't really been done before - and its slow burn narrative, which catches people offguard who were expecting a bloodbath from the word 'go'. The first film is a prime example of what you can do with a little ingenuity, as a filmmaker - the kind of "beg, borrow and steal" philosophy that motivated Robert Rodriguez to make El Mariachi - and also introduced an entirely new way of shooting car chases, which is entirely Miller's own that he developed further with the next two in the series, to greater effect.