I think you're right --- Google won't get enough independent (unbiased) reviewers. The reviews will be the business owner and a few of his friends or employees writing positive reviews -- and competitors writing negative reviews.
Someone really needs to go after pure search while GOOG is going after everything else.
Then GOOG will have to rank for "reviews", "places", "social networking", "books", blogs, and everything else according the new search engine's algorithm.
I don't think any one company can dethrone Google in search -- but I'll say it again: a "distributed search engine", one made up of hundreds or thousands of people's databases of sites, (people like "webmasters"), who can edit categories of listings and pull all the data together under a single "engine" can.
...and of course it will need a centralized advertising system to monetize it.
Expect a standardized "Facebook Business Reviews" app and a push to get FB users to review stuff in a systematic way next.