It's hot as fuck and I've had far too much orange juice. Like, a carton and a half's worth. I think I'm going to vomit. Just for context.
To answer your specific points:
Furiosa was Immortan Joe's Imperator - i.e. general, captain, or officer of some description - so they obviously had a pre-existing relationship. I thought it was an odd choice of badass one-liner but I didn't think it implied anything beyond that. Immortan Joe is a piece of shit and Furiosa's been his reluctant lacky up until that very day.
One of the best things about the movie was how concise it was - it established things as it went along and expected the audience to keep up, which I don't think was an unreasonable expectatio, considering how simple the set-up is and how heavily stylised everything is, which leads me onto your point about the plot:
The plot wasn't the chase; the chase was the vehicle for the plot to unfold. Everything was communicated through action. I don't know why you brought up Jurassic Park; lots of films have chases. The Road Warrior predates Jurassic Park by over a decade and has an awesome, long chase at the end.
As for character development, each of the main characters ended the film in a completely different place to where they started it:
There's reluctant heroes and then there's Max; who's a loner whose only motivation is survival; who gets captured, tied to the front of a car and gets his blood stolen from him; who tries to leave Furiosa and the brides for dead (and tries to shoot Nux's arm off); who allies with Furiosa out of necessity, essentially holding them hostage; who becomes more and more protective as the movie goes on; who gets to the point that, in a moment of desperation, risks himself being left behind to save the others; who becomes, more or less, bros with Furiosa; who willing gives his blood to save Furiosa; who disappears into the crowd to carry on his wandering.
There's Furiosa's road to redemption, her betrayal of Immortan Joe, her grudging co-operation with Max, her alliance with Max, her despair, her fall, and her ultimate rise to glory.
Nux has probably the most obvious arc, being the most talkative character, and going from a jobber heel to a midcard babyface and ultimately getting the awesome suicide he always wanted, just in a different way.
Oh, and there's the Citadel, which produces food and water, ruled by Immortan Joe, and the Bullet Farm and Gas Town, and you can probably gues what they do, which are both ruled over by Immortan Joe's inbred cousins (because they're all pricks).
I've got to go grill a chicken on the pavement or something.