MS cut a lot of fat, but it was hardly surprising.
I said it before, pre-announcing Halo 5 Guardians and Forza Horizon 2 didn't mean jack shit. The fact that both games were not given substantial trailers clearly meant that time would be allocated at the conference for both games. They weren't moved out of the conference, they were just announced earlier.
The other thing that killed it was well... ntkrl, that stupid Gamestop rumour of 3rd-party exclusive, and the self-feeding hype.
Say whatever you all want, ntkrl spoiling everything meant you all knew what to expect. And that led you to expect more out of it, especially with Phil Spencer hyping his show as if there's going to be 60 minutes of exclusive games non-stop, and more than what was leaked. As if there were a ton of megatons. Everything turned out to be practically what the leak said it was, and CGi trailers also meant that there's an inner scepticism that PD, Scalebound and Crackdown will be 2015.