This is indeed pretty good news.
In terms of Backward Compatibility with the Xbox One, Xbox 360 games are now going to come out as they are ready instead of gamers having to wait the full monthly time frame.
Based on your feedback, the Xbox Engineering team will start to pilot a new way to launch Xbox One Backward Compatibility titles. Starting today, we’ll release titles as they become available, rather than a set monthly launch date. What this means for you is that you won’t have to wait to find out the latest titles; we’ll release whatever is available, when they’re available, once each title has received the engineering and publisher stamp of approval.
The Witcher 2: Assassins of Kings is also available until February 5 (8am GMT) for free at Xbox.com, if you live in either the US, UK, Canada, France or Germany.
More information here – https://news.xbox.com/2016/01/21/xbox-one-backward-compatibility-january/