Microsoft announced via Twitter during the weekend that button mapping is coming to Xbox One controllers. It was previously known that this feature would be available for the Xbox One Elite controllers, but it is in fact not limited to those and you will shortly be able to customise everything as you want it.
PlayStation 4 users already have this feature, and it has been one och the more requested ones for Xbox One, and it is of course nice to see Microsoft listening to their community. As Xbox One Elite controllers are due out at the end of the month, hopefully this feature will land around the same time.