I am fortunate to be able to say I'm a recovered X-axis inverter. It's unfortunate that I actually had to recover from such an affliction, but with the limited control options offered to gamers these days, I didn't have much of a choice if I wanted to continue playing games.
Many times, my need to invert the X axis came as shock and confusion to anyone that heard about it. They couldn't comprehend why I would possibly need to make my controls completely backwards but for me it was totally natural and logical. Here is the picture I ended up using to illustrate why my handicap was legit:
Imagine our dapper little scientists up there are manning their ray guns when suddenly a UFO appears! Look! Up in the sky! Over to the left! As they aim their ray guns at this UFO to the upper-left corner of the sky, think about where they're pushing their handles. Yep, down and to the right. Now apply this to games: To my mind's eye, that protective shield they're standing behind is the TV screen and the handles they're pushing are the analog sticks on the controller. The barrel of the ray guns would obviously represent the on-screen gun. When I played a shooter I controlled the gun, not the reticle.
What amazes me is that developers decide to include the option to invert one axis but not the other. Would it really be that much of a burden to take that one extra step?
But now that I've recovered and am able to play any game I desire, it's made me wonder why in the world these developers don't just open up the controls completely and let us remap to our heart's content. BioShock on the PS3 forced you to use the triggers to fire your weapons, and a lot of people would have rather used R1 and L1. How hard would it have been to accommodate that? What if I wanted to set my "hijack car" button to the Start button in Grand Theft Auto IV? Why not?
I'd love to see this actually happen. What if a game's tutorial were completely flipped around such that the on-screen character would perform a move, and then prompt the player to choose which button on the controller they'd like to set for that action? Sure, give a recommended default but why force us to be uncomfortable if there's a way to avoid it?
Of all the trends that have come and gone over the years in gaming like colored lighting and bump mapping and environmental destruction, how many have been designed to accommodate the wide variety of players and their many comforts? How about starting with something like this?