This sort of forced the hands of the BeagleBone Black developers, as they wouldn't be able to get a new ARM board file admitted into the mainline of the Linux kernel. They then decided to implement the DT in the latest kernel version released with the BeagleBone Black (currently using 3.8).
One issue discovered with the DT was that it wasn't designed for open embedded systems that needed to modify the system (muxing pins, enabling devices, etc) during run-time. Pantelis Antoniu implemented a solution to this issue using device tree overlays, and a cape manager. Later, Grant Likely proposed the system that would allow for a new device tree overlay format that was a "direct extension from the existing dtb data format." allowing for modification of the DT during run-time from user-space.
More details about the history, and implementation details can be found at the following links: