Yes, I noticed that the template is not used a while ago as well: https://github.com/pkp/pkp-lib/issues/2406
I think that the issue in general will need more work later, but in OJS 3.1 there will be some changes that have been discussed here https://github.com/pkp/pkp-lib/issues/2561#issuecomment-331238325. Basically when publishing a new issue or adding a new annoucement the editor can now choose whether she wants to send a notification email. I think that most are happy already with this change.
I do agree that the notification for a new issue should be a longer email and maybe use the template you mentioned.