So moderators just got the ability to provide custom reasons when they ban users from review. Often, these bans are due to specific very bad reviews, like approving spam or non-answers. It will be common for us to give links to these bad reviews in the ban message that the reviewers will be presented with.
However, many of these reviewers lack the necessary reputation to see deleted posts. If we're banning someone from review for approving spam or non-answers, almost all of the time those posts will be deleted. If we give them links to the reviews they performed, they won't see the now-deleted posts that they approved, and won't have a chance to learn what they did wrong.
I propose that reviewers of any reputation level be able to see posts that they reviewed, even ones that were later deleted, if they are presented with a link to their review. They already saw the post once, so there's no harm in showing it to them again, and reviewers are going to need to see why they made a bad call on a particular review.