Just looking at the search bar and type status:deleted makes me a little annoyed, it's like looking at spoiled food and knowing that it'll never decompose entirely. I propose that any post that's been deleted for a very long time (say 5 or 10 years) it'll be removed from the server completely, freeing up spaces.
And if anyone wants to see those deleted images/videos/comments, maybe use a Wayback Machine instead.