I think the most revealing thing in the package is Widmore wanting to keep the MiB on the island, putting him on the side of Jacob. This may mean Ben was always on the side of the MiB, and him being Jacob's killer goes with that, but remember we have a strange three factor war.
There is Jacob v MiB, but then there is the scientific interloper that wants access to the island because of its powers, just as enabling time travel. I further get the strong impression that Widmore's side is the Dharma side, and not jacobs, but perhaps his history in more than one group makes him knowledgable that the MiB's escape is in no one's best interest.
The fact that Widmore has a scientist in charge, and that the show emphasized that, gave me this impression. Perhaps Widmore, in his off island escapades betrayed the island this way, is the ultimate reason it was revealed to Dharma, though he perhaps was banned for some other lessor crime.
Finally, I think a big picture is focusing regarding the island being a center of history, pivotal in how history turns out, how the end happens, even if after there is just another starting over toward a new end. The MiB and Jacob represent a dichotomy from classic religious ideas of good and bad behavior, while Dharma represents the secular approach, with its flaws and sensibilities.
In summary, we have seen a clarification between the jacob v MiB teams, and now understand Widmore's team. Given no one else seems to be cooperating with him, his desire to keep MiB on the island is merely coincidental alliance of interest with Jacob's team. So I wonder what Jacob thinks of Widmore.