Regarding risks, I think you're understating the sophistication and importance of risks on flight projects. (I work at JPL, but not on flight projects; once upon a time, the OP's office was right down the hall from mine.) A modest sized flight project will have a risk list which is itemized down to great detail, covering many pages, and this list will be one of the main things the mission managers work on reducing.
In general, there are two parameters, likelihood of the risk materializing, and cost if it does. Sometimes the cost is easier to bear (dollars and schedule), sometimes it's harder (lose the mission). For units like dollars and schedule, it does make sense to do a weighted average (sum over risks of probability * cost); for others it does not. People go farther and use various Monte Carlo methods to deal with risks that interact, so that the sum above does not work.
In general, there are two parameters, likelihood of the risk materializing, and cost if it does. Sometimes the cost is easier to bear (dollars and schedule), sometimes it's harder (lose the mission). For units like dollars and schedule, it does make sense to do a weighted average (sum over risks of probability * cost); for others it does not. People go farther and use various Monte Carlo methods to deal with risks that interact, so that the sum above does not work.
Here's someone at JPL who's in that area:
http://www.usc.edu/dept/ise/directory/jairus_hihn.htm