Both my AF-ON buttons have the same spring loaded feel. In fact all the pairs of duplicated controls have the same feel and sound.
I'm, not sure what you mean by the main-command dial. To me that's the rotating wheel just below the shutter release. It only goes left and right. Do you mean the 8 direction multi-selector with the small button in the middle? On my D4 all directions and the center button have the same feel with a barely audible click.
I think you have problems that need to be fixed
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