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Every time Google changes its policies or algorithms, some people will find those changes to be positive and others will complain that they are negative. There will often be truth to both sides. A change which increases the relevance or profitability for one publisher may have the opposite effect, or result in vastly increased PSA's, for another. A change, such as broad matching, which may significantly reduce the average cost per click for one advertiser may significantly increase the cost per click of another.
Ultimately, given the relative ease by which people can track the performance of AdSense and AdWords, the market will dictate the success of those programs, and additional changes will occur as Google attempts to improve the programs to maximize profitability and relevance. (And with every change, no matter how minor, we are likely to hear complaints.)