SPOILER warning - Im more than half way through the game so some reference is made to later stuff if you're just starting.

There are some really odd gameplay elements in RAGE that make me think what on earth were the devs thinking ?

Firstly - health.
Bandages don't heal - they stop bleeding so bandages having a quick heal effect is dumb.
You have these nanites that heal you in your body right - so replace the bandages with adrenaline that speeds up the nanites - a little more logical.
Having regenerative health and bandages and the defib minigame is overkill - the defib doesnt work properly on the PC - scrap it.
No health bar? Your car has a health bar but you don't?! So whats the point of making the Apophis Infusion? It increases health you cannot see!

Second - garages
There are 2 garages in each town so you have to go to and fro to get your car repaired and upgraded but the upgrades you buy at one garage
are automatically applied while your car is in the other garage - doesn't make any sense.
Answer - one garage - get your slips and take em back to the garage at the town entrance where you get all repairs and upgrades handled
and while you're at it - allow me to trade in old parts for 25% when I do upgrades.
And put a workbench in the garage - that's where you do your engineering so you outfit your car and your kit *before* heading out on a mission.
The idea that you can collect stuff and make fancy items anywhere you like without tools or a workbench - daft.

Third - weapons
This is a world destroyed by a cataclysm - the factories are gone so dispense with the hi-tech weapons and give us more lo-tech stuff
Melee would be a must and a boomerang is fine - crossbow ? Sure but no electro bolts please. Fire weapons would be a must - molotovs and scrap the frag grenades.
TWO assault rifles? Why? One is plenty but give a variety of ammo for different enemies including armor piercing.
Rocket launchers? Maybe but only when fighting against a hi-tech enemy like the Authority - in their territory you kill them and scavenge their weapons so thats when you get the fancy stuff.

Fourth - the Authority
I've met the resistance now but still the Authority hasn't been properly explained - they're just the bad guys in this game - their motives and goals are a mystery.
I know they want me dead but why?

So Im running and driving around in this very pretty game (now that its been tweaked to stop the horrible texture loading) and I am having fun
but honestly - it could have been a lot better with just a little more thought.

Sorry you may not like some of the answers but...

To be fair everyone knows what Bandages in a game means, they are healing iteams. Giving someone a item called adrenaline would most likely confuse people at the start thinking it would give you infinite run or something. Adrenaline as something that restores my hp is not my first thought. I also had no trouble with the Defib and I'm playing on the PC, I think its fine and adds some flavor. My one complaint is just the fact they have regen hp in a id software title. More of a health pack fan myself

I also think you might be taking it a tad far with the realism aspect here dude. Complaining about having the upgrades tranfer to other garages seems insanely nit picky. What you are suggesting would slow gameplay quite a bit. FPS games such as Rage, Half life 2, Halo etc are meant to get you into action quickly and start killing things.

As for weapons, would be kind of a lame game if you had no cool weapons, when I think of id software FPS I think of Miniguns and BFG's. I want a beasty shotgun and I want to send a mutant into orbit with the aid of my trusty rocket laucher, not really into the whole hey I'm gonna take this bat with 3 rail road spikes in it and try to kill that 10 foot mutant with the fire ball laucher, I'll play Silent hill for that
Not to mention this game is what.... 120 years tops after the astroid hit the earth? Weapons and factories would still be around. Replacement parts prob not to insanely hard to find. Not to mention the people that survived would probably have a fairly good idea how to pick up the pieces. Not to mention given the supplies or the means to make any of that stuff, humans will do it. So I would say electro bolts arent the most absurd ammo type you would find. Mind control bolts yeah I would say thats a wee bit iffy. But if you've gotten far enough in the game I think you can forgive how they came into the world.

As for the Authority

From what it looks like id software is prob going to make this a trilogy, you don't give away all of the plot elements and good bits in episode one Also you can read the book, might help you out some.

you didn't read me right - what Im suggesting is one garage per town that handles all repairs and upgrades. It would simplify and speed up that aspect of the game NOT slow things down.

something like the garage in Hagars town is what I envisage - drive in and hop out - talk to the guy behind the counter about repairs and upgrades then go into town to trade and get quests
- rather than the system for the bigger towns - drive in and go through a menu screen to decide whether you want to repair and where to exit to .... that slows the game down
and then you have to go to another garage to buy upgrades.

Fifth (just remembered this one)

Voices - The game is set in the USA (or so I gather) so the good guys are American (somewhat predictable but understandable)
but why do all the baddies speak with Brit, Aussie or German accents?

What is it about the American mentality that they always make the baddies Brits, Germans or whatever.
Maybe Carmack and Co should take a holiday *outside* the USA for once and have their eyes opened.