In case it wasn't just an accident (god knows I do it myself on occasion), when you move a subpage to the correct work, if you uncheck the "create a redirect" option before proceeding, you won't need to throw a delete template up on the original page location.
Topic on User talk:NotaBene
I looked for that option (I'm accustomed to having it on other wikis I edit), but didn't see it. Looking at e.g. moving Kantai Collection, I have options to move the subpages (or not) and watch the source and destination pages (or not), but no option not to leave a redirect. Is that permission restricted in this wiki's configuration?
Weird. If it's a configuration thing, I'll have to ask @Labster about it. This is the first I've heard of anyone not having the option on the move page.
That's normal. It's the suppressredirect user right. I have no problem handing out that permission to you. I have no idea whether handing that to confirmed accounts by default would be a good idea or not.
Most page moves should leave behind a redirect (if we're moving a work or trope to a new name); this was a corner case where I was moving a subpage to be a subpage of another work (COPS the reality TV show vs. COPS the cartoon), and having a redirect would have been inappropriate.
If a page gets moved without a redirect (when it should have a redirect), and breaks a bunch of links, we can just make the redirect afterwards, but I have seen a wiki vandalized by a confirmed user spamming page moves (without leaving redirects) and scrambling up their histories in the process. (In the end, after he was blocked, we rolled back to a previous backup and 'lost' the week prior to the attack.)
If my experiences are any indication -- and they may not, because I've never looked into seeing what is different between admin defaults and confirmed user defaults are -- but if they are, then creating a redirect is on by default and has to be explicitly undone. So anyone who spams page moves like that would have to be deliberately breaking things.