Gaming Blend reported that Rob Semsey stated:
The reason behind the lack of announcing a Halo title? They weren't sure on the official name.
Apparently, the reasoning for the fact that they didn't name Halo in the games that were announced earlier, along with the announcement that they had sold # million Xbox Ones:Rest assured your next Halo journey WILL begin in 2014. #staycalm
"We’re excited for the year ahead and will be working hard to bring Xbox One to more fans and more markets around the globe," the company said. "2014 will be a promising year with many more great games on the way for Xbox One including Titanfall, Watch_Dogs, Project Spark, Sunset Overdrive, Tom Clancy’s The Division, The Witcher 3: Wild Hunt, Destiny, Plants vs. Zombies: Garden Warfare, and The Elder Scrolls Online, among others. More games, more features, more content, more fun – all coming your way this year."
The reason behind the lack of announcing a Halo title? They weren't sure on the official name.