I have been using Google Adwords for over a year and I agree completely with your complaint. As of several months ago, Google has continually placed three of our keywords in their "at risk" category. The keywords are fully optimized and clearly define our business. We have followed all of the suggestions offered by Google to "optimize" our ads/keyword etc. when we finally realized that the "solution" to the problem was incresing the price-per-click rate. We have contacted Google regarding this obvious irony. They confirmed the fact. Basically, it all boils down to, "the more you pay", the higher you will appear in the list, and thus the more chances you will have of someone clicking on your ad. A very expensive solution indeed.