Well, it seems that I am a little late to the table on this one.
Rubicon exemplifies the best in TV drama and also the worst, and part of it is the structure. You have a conspiracy theory that involves most of the characters in the story, you have what kind of amounts to a locked room atmosphere, you want to create a sense of peril and the impression that your heroes are in danger – this is what any drama wants. But you are a series and you want to be commissioned for a second series, so maybe near the end you start to get a little cautious and then the whole machinery and the mystery collapses in the middle like a soufflĂ©
It started off brilliantly but it felt like it threw it away. It is a shame it was not renewed for a second series – it would have been interesting to see how it progressed and how the characters developed, and whether the second series fell prey to the same issues.