Thanks for bringing up this point - I agree Eric - competitive positioning can help you determine value that you bring to the table that your competitors dont.  I'm all for it.  Neilsen does some reports that provide awareness, likelihood to recommend, sentiment and other insightsfor your site/brand and your competitors. You can also pull some of that type of insight out of social listening platforms like NetBase, SM2, Radian6, Dow Jones, Nielsen, and so many others.  I've even done some hacked compeitove sentiment comprisons before using Search: searching for [brand or feature] + "like", "love", hate", "wish" etc. 

By relying so much on factors such as keyword density which were exclusively within a webmaster's control, early search engines suffered from abuse and ranking manipulation. To provide better results to their users, search engines had to adapt to ensure their results pages showed the most relevant search results, rather than unrelated pages stuffed with numerous keywords by unscrupulous webmasters. This meant moving away from heavy reliance on term density to a more holistic process for scoring semantic signals.[13] Since the success and popularity of a search engine is determined by its ability to produce the most relevant results to any given search, poor quality or irrelevant search results could lead users to find other search sources. Search engines responded by developing more complex ranking algorithms, taking into account additional factors that were more difficult for webmasters to manipulate. In 2005, an annual conference, AIRWeb (Adversarial Information Retrieval on the Web), was created to bring together practitioners and researchers concerned with search engine optimization and related topics.[14]

Lastly, it's important to remember that paralysis by over-thinking is a real issue some struggle with. There's no pill for it (yet). Predicting perfection is a fool's errand. Get as close as you can within a reasonable timeframe, and prepare for future iteration. If you're traveling through your plan and determine a soft spot at any time, simply pivot. It's many hours of upfront work to get your strategy built, but it's not too hard to tweak as you go.