I recently installed the windows 10 Technical Preview, and downloaded FIFA 15 ultimate team from the Windows app store. I would like to know if it is possible to play the game with an external USB controller with this Operating System or with Windows 8, 8.1
Yes you can.
I wondered also about this problem, but if you go to the windows site it says: 'Plus, if you have an external controller – don’t miss the chance to use it on the pitch for the first time. It’s your match to play!'