♦ mods can see deleted posts in search results, but the posts don't show any indication that they've been deleted (e.g., see https://stackoverflow.com/search?q=deleted%3A1). It would be nice if posts on the search results page were styled the same way as deleted posts elsewhere on the site
Sometime in the years since this question was asked, this was implemented. Here's an example from my own posts on EL&U (where I have 10k and can thus see my deleted posts):
Deleted posts are styled with the pink background, same as they are on the question page itself and in other places where people (usually just moderators) can see deleted content.
deleted:all search parameter works for anybody who can see deleted posts, not just for moderators. For non-moderators it shows only your own posts. If you have any deleted posts on a site where you have that privilege, you can verify the styling. (I'm not a moderator on EL&U, where I took that screenshot.)