Lock questions in the review queue while being reviewed
A number of questions in the "first posts" category often require significant attention to make them more easily understood. If a reviewer decides to edit the post there's a good chance that during the edit someone else could "steal" (for lack of a better word) the review with a simple upvote/downvote or by leaving a short comment.
My suggestion is to somehow block other users from reviewing that post while the edit is taking place. This would allow reviewers to take the necessary time to properly copy-edit a difficult to read post without losing credit for the review.