inverted control is a perversion of flight stimulation games....
in reality, flight stimulation games should come with a flight stick, i.e. you pull or push the stick up and down, rather than using your game controller pad to do it. On the control pad, you're not pulling the stick up, you're pressing the down button, big difference!
because we all know that buying a flight controller for the flight games is not ideal option (in the past), that's why we went with the inverted control...
for that reason, i even play flight simulator with the normal setting (unless i'm using a flight controller).
for people play a lot of platformers, it's a bit difficult to grasp the idea that pressing up means to go down and pressing down means to go up.
FPS games are not flight stimulators, so it's not natural to invert the control. Of course, in the first person perspective mode, the gamer feels a bit like in a cockpit or something similar and hence want the buttons to be inverted.
Now, a better FPS game would be a gun controller (similar to a Wiimote) and a head visor/gear. The head gear controls left and right of the player's direction. The gun's movement (in the gamer's hand) controls the gun. To walk straight or jump, there could be a feet pad or simply a button on the gun controller (no, not nunchuck, but a button on the barrel or handle).