My only worry about funding FHI exclusively is that they are primarily philosophical and academic. I'd worry that the default thing they would do with more money would be to produce more philosophical papers. Rather than say doing/funding biological research or programming, if that was what was needed.

But as the incentive structures for x-risk reduction organisations go, those of an academic philosophy department aren't too bad at this stage.

This seems to work as an argument for much greater marginal worth of ensuring minimal funding, so that there is at least someone who researches the uncertainties professionally (to improve on what people from the street can estimate in their spare time), before we ask about the value of researching the stuff these uncertainties are about. (Of course, being the same organization that directly benefits from a given answer is generally a bad idea, so FHI might work in this case.)

The FHI's pitch: http://www.fhi.ox.ac.uk/get_involved