User blog comment:Damac1214/Back in Black - Call of Duty: Black Ops III teased, reveal trailer coming April 26th/@comment-3171236-20150410061314/@comment-3171236-20150410192152

Yeah, my guess is the final intel piece from Black Ops (the Charybdis letter) stemmed from an early concept of Black Ops II in which Treyarch toyed around with the idea of Mason, Weaver and Hudson being hunted by the CIA and Soviet KGB agents throughout Africa, the Middle East and Central America through the tumultuous 1980s. Evidently, the concept of Mason still being brainwashed and it affecting him years later was retained, but not in a very significant state in the final game. The other concept of the Op 40 team in the 1980s was also kept, but it mostly served to provide Menendez's background.

With some fleshed out details, antagonists, good setpieces (even something like the Falklands could have been used as a level, considering MI6 was listed as being involved in Charybdis), it could have made for an interesting sequel to Black Ops in its own right. However, I guess the Menendez concept alongside a futuristic setting involving drones, high-tech weapons and a well-funded OWS-like terrorist group probably interested Treyarch more in the end.

The only thing that remains unexplained is why Weaver did not appear and was never once mentioned in Black Ops II. He was a pretty significant character, and Treyarch went to lengths to show how Woods survived a belt of grenades exploding close by (as Woods was a fan-favorite, alongsie Bowman who might have been brought back if he was not clubbed to death in Black Ops).