I doubt it will be as great as The Fog of War, but then again how could it? That documentary had the advantage of historical perspective, a subject willing to go right up the edge of apology -- and with all due respect to those killed on 9/11 and in Iraq and Afghanistan -- a more compelling subject matter.
Someone did an Errol Morris style doc on Dick Cheney recently that I watched. That one didn't do much for me. Cheney is a wall, and the only worthy lesson to be derived from a guy like him is that confidence is much more important than competence. Cheney is almost a Chauncey Gardiner (from Being There) type, someone who comes off so calm, so assured, so right... that people assume he must know what he's doing. Never mind that Cheney screwed up basically everything he touched during his entire career, which itself was only down to a chance meeting with Donald Rumsfeld. Even Bush eventually realized that Cheney was a moron and a crackpot.