You certainly can often do better than individual experts by averaging experts, but BDM's methods actually do add something.
To the extent that BDM predicts things like the Khomeini succession (and something about the Indian parliament, if I recall one of my political economy classes) in ways nobody else sees, including himself, it's worth understanding just how game theory allows unexpected or unintuitive results from completely basic inputs.
BDM's use of experts is confined to the inputs--a place where their judgments are more straightforward. It is rather easier to compare the relative power of two parliamentarians, for instance, than to predict the outcome of a multiparty election. Averaging experts' opinions on the latter may not improve forecasts much, and that's where BDM's innovations have been useful.
I should note too that he sometimes derives the model inputs himself.
I don't want to oversell his abilities, but he's doing pretty innovative work at the cutting edge of political economic theory.
To clarify the last point, I particularly recommend examining the selectorate theory in The Logic of Political Survival, chapters 2 and 3, and "Political Survival and Endogenous Institutional Change" in Comparative Political Studies 2008.
Both are from a recent course I took on political economy.
I stumbled upon an article called The New Nostradamus, reporting of a game-theoretic model which predicts political outcomes with startling effectiveness. The results are very impressive. However, the site hosting the article is unfamiliar to me, so I'm not certain of the article's verity, but a quick Google seems to support the claims, at least on a superficial skimming. Here's his TED talk. The model seems almost too good to be true, though. Anybody know more?
Some choice bits from the article:
The claim:
The results:
Gets good money for it:
The method should be of special interest to the OB/LW audience, as it brings to mind discussions about self-deception and evolutionary vs. acknowledged goals and behavior: