Editing posts (by contributors) should create a new revision

When someone with the user role Contributor makes changes to an already published post, that post gets unpublished and gets reverted to draft. This basically removes the post from the website (for visitors at least) until the changes are approved by the Admin.

Instead of this, why not make it so that the Contributor simply makes a new revision of the post. When the revision is approved, it simply replaces the old version, but throughout the process, the original post is still published and is accessible by the visitors.