I did the same thing. I hadn't gamed for over a year, and I was someone who played games their entire life and played multiple FPS's competitively but thought I was pretty much done with games for good. When I saw the MCC, I knew I had to have a dedicated Halo Box as it were since I'm a gigantic Halo fan.
But in the end, they fucked up beyond anyone's wildest worst case scenario. I did the same thing, got Live, got the headset, play and charge, extra controller.
I have however, managed to play a few games that I enjoyed, COD:AW, Far Cry 4 (which is incredible) BF4 and PvZ: Garden Warfare. All that being said, I pretty much bought those games because I had already thrown so much money into the X1, I didn't want to just have that money become a sunk cost.
At this point, my X1 is a dedicated WWE Network box (though I already had multiple consoles that could run the app) with maybe 5 hours of gaming on it per week.
As for the OS, goddamn, I wish I did more research on it, caz wow, what an absolute piece of shit OS.
TL;dr: If you bought the X1 for MCC, you will/are having a bad time.