(1) is mostly solved by valuing long, well written reviews over star ratings and allowing users to upvote / downvote. You can also allow up voting / down voting

(1) is mostly solved by valuing long, well written reviews over star ratings and allowing users to upvote / downvote. You can also allow up voting / down voting of user-posted reviews to create a reputational penalty for non-useful reviews. (4) is addressed by volume. That's easier for something like restaurants than apartments or recruiters though.