I guess by today's standards it's a "slow burn" but not excessively so. The whole thing is suffused with dread and tension, and there's PLENTY of car action (my oldest said "I think the writer really needed a plot to string together some cool car chases." He said this with some admiration). Both my kids did great with ALIEN, and that's a MUCH slower burn than Mad Max.
I think they were "meh" partly because of the lack of eye catching design, and partly because they couldn't understand a lot of the dialogue (the youngest admitted to being lost whenever people spoke most of the time).
Long story short, I don't think they've ever seen a foreign film, and certainly not a low budget 70s flick (they've seen bigger budget fare like Star Wars--the ORIGINAL OT, thank you very much-- and ALIEN), and having started them on Thunderdome, they were looking for something more overdesigned and grandiose.
Whatever...I enjoyed taking my Max blu-ray for a spin
And they definitely appreciated the practical stunts. My youngest is decidedly "retro" in his aesthetics and is very taken with old school effects. So they had a lot of praise for the car/motorcycle mayhem the crazy stuntmen pulled off.