The whole Jimi idea with reverse headstock was actually the body itself so he had closer control to the knobs. The rest is really cosmetics -- me thinks it's nothing special, could even be silly in some configs.
I think the Reversed Headstock works better on in-line tuner setups. Very practical but I'm just used to the 2x4/2x5 setup I have on my guitars right now. It was really weird at first adjusting with my first JP6, but it became way natural after a few weeks with it!