One option is to allow sorting on different facets, and default to one that levels the playing field a bit.

For example, instead of showing the tutors with the highest ratings, perhaps you could show the tutors with the highest ratings in the last 14 days (average of the last 14 days' reviews only), or those with the most activity on the site in the last X days (using Clarity as an example, show people who are actively answering questions).

The option to see "highest rated" or "most reviewed" should still exist, but you can give your new folks a chance by creating a metric they can compete on if there's a short history option.

The catch with this, of course, is that you open the door for gaming the system by spammers or less ethical folks, so be ready to set clear guidelines and to make examples of people who abuse the filters.

Good luck!