Thing is, it's about time to leave behind these legacy restrictions and use today's possibilities for user interface design and customisation. I was also negatively surprised by this not being possible on the 1DX. And I don't understand why I can't freely configure ANY function to ANY button, with some macro/script-capabilities added on top! Imagine if all the functions of the camera where available inside a Lua interpreter, and you could assign any Lua-script to any button! If they gave me the source I'd hack that together in no time :-) At least if the original firmware is in C...