So the idea, other than just providing the deletion log if a wiki was deleted, is to provide something along the lines of the old Wikia home page with image links to related and big wikis.

So NoSuchWiki no longer uses HTTP_REFERER as browsers don't set this often enough for this to be reliable.

In T74#941, @jack wrote:

Assuming most of our log entries are written to be "user safe", there should be nothing wrong with exposing the reason and date behind a wiki deletion (or multiple if that is the case).

They probably are (although I wouldn't want to go through all of them, or write a script to dump 'em either), but a lot of the time the reason isn't even interesting. A lot of them are like "request" or "ticket #so-and-so" or something like that -- obviously the deletion was requested since creators can't delete their wikis, and osTicket is a private communication channel between users and us; a user isn't able to view tickets created by others, so the fact that a wiki was deleted due to "osTicket #9803280" tells them absolutely nothing, I'm afraid.

We should consider that the creator/admin isn't going to be the only one looking at a wiki.

This is obviously true, hence why Special:DeleteWiki is staff-only instead of something that'd allow admins/stewards to delete any wiki that they've created.