Sometimes the best way forward is to look at your past successes. IMHO, Microsoft need to bring back the "all about games" feeling it had on the Xbox and early years of Xbox 360. Sure, it's great the Xbox One can play all my media, but that isn't why l choose a console. It's the games and the variety of games it has.
Xbox - Appearance and Design
The look of the console/dashboard felt like it was future tech and game oriented. Sure, consoles at this point weren't seen as media hubs too but even today this thing looks like a beast. The inclusion of 4 controller ports also gave it a leg up fo CO-OP play. Xbox Live was also well thought out and was (from memory) a painless experience to play MP against your friends. Even Local CO-OP/MP was well supported and easy to do (If you had the right cables

).
Xbox - Games
The games were genre defining (re: Halo, PGR) and visually stunning. They also covered a WIDE range of genres as can be seen above. There was a unique and often exclusive experience for everyone.
Xbox 360 - Appearance and Design
While not as bulky/beastly as the original, the first 360 design still looked like a games console. The "blades" dashboard also gave the impression of speed and game first. Xbox Live also grew from the original Xbox and it's offering of Arcade titles further increased the appeal.
Xbox 360 - Games
It's probably the fanboy inside me but no console has matched the 360 in terms of games. It simply had a little something for everyone.
Xbox One
To me, the design of the Xbox One is something that was destined to fit into the living room. Even the dashboard. If they want to change my opinion of how Microsoft see the Xbox brand, they need to remove the advertising and clutter. Show me you see the xbox as a games machine, not an all in one device first.