It is just a personal thing, but for me, Mechwarrior is best played with two Joysticks! Here is a short guide on how to make Mechwarrior 5 work with two Joysticks aka HOTAS, using a virtual joystick driver (VJoy), a Tool named Joystick Gremlin and some file editing!
My MW5 dual stick setup:
1) For right hand (I am right-handed) : a good old MS Sidewinder Force Feedback Pro 2, which works still with Win 10. This is a mechanical joystick with motors, which makes it precise. They are on eBay.
2) left hand: precision is not so important but needs to be adjustable for left hand: T16000M
3) Install VJoy: https://www.vjoy.org/ (virtual Joystick driver)
4) Install Joystick Gremlin: https://whitemagic.github.io/JoystickGremlin/ (Allows remapping of devices to another device, like keyboard to game pad, etc.)
5) In Joystick Gremlin: Mapping the Sidewinder Pro 2 to the virtual Joystick in VJoy Make a new profile and a remap for every button, axis, etc. only the cooli-hat doesn't work to remap
6) HOTAS File in MW5: Download and drop the HOTASMappings.Remap into the SavedHOTAS directory: C:\Users\<yourWindowsUserName>\AppData\Local\MW5Mercs\Saved\SavedHOTAS
7) Before starting MW5 each time, aim the Gremlin (2nd button on top, icon game pad > turns green) This switches on the remapping.
8) And then you must do the controls' config in MW5, simply in the game's settings under controls. After you have done that, backup your input.ini and GameUserSettings.ini