I don't know about you, but I receive 40~ of these damned things a day. (5x 8 characters) Not only do you have to log in to each character (and spam the crap out of your friends list) but you also have to collect them all. Even when I didn't have 40/day it was still a pain to do it every day, thus I propose a simple solution:
New bank function: Mail delivery - All hireling mails in one place and NOT your main mailbox.
(for ZoS: to implement this quickly, allow all deliveries on the account on first login of any character, increase mailbox size to accommodate, new flag for mails IS_HIRELING. If you're in your main mailbox filter these out, if you're in the bank one, filter normal mails. Simple hack but it'll work)
Now we don't have to spam our friends list logging in to every character, RPers and those who want to can still read the stories from the hirelings and get their stuff in one central location and people who don't want to see them all the time and get spammed with crap constantly can keep things organized.
Hireling mails are a quick hack to get things working. I know this, other programmers know this, the guy at ZoS who made the system knows this, so why not polish the system up and make it easier and less cluttered? Simple quality of life enhancements shouldn't always be covered by addons like PostMaster.
So, lets make things easier for everyone eh?