I would like to suggest an account-wide storage that would be accessible to all characters following the same rule set of the mailing system. This bank would be accessible from a tab within the Collections interface, and it would be divided into sub-categories of professions and/or materials for each expansion. Again, the bank would function the same way the mailing operations function when it comes to mailing basic BoE items such as Copper Ore. I understand that this doesn’t fit the definition of ‘account-wide’ perfectly, so maybe a better term is ‘Server-and-faction-specific-storage’.
I created the image below roughly picturing what something like this would look like in game:
Server-and-Faction-Specific Storage
As an example of functionality, let’s say that I farm up and deposit 200 Copper Ore into this storage on my Death Knight. I would then be able to log onto my Warrior (which is the same faction and server) and withdrawal from that stack of Copper Ore – all without having to leave my farming location and/or travel to mailbox with either character. Something I would not be able to do is withdrawal this ore with a character on the opposite faction nor a character on the same faction but on a different realm.
I considered listing out the 20+ benefits this would provide players in the saving of bank space and time, but I think most of that is self-evident at this point. However, there is a benefit that would directly impact GMs as well as players! Everyday players mail ores, herbs, leather, and other profession materials to their alts. And every day, someone accidently sends these materials to a guildmate who has been offline for 6 months or to a random person with a similar name as their alt. These accidental mailings of materials to other players results in tickets requesting the recovery of items and GMs losing time investigating and correcting an otherwise avoidable problem. While this account-wide bank may not prevent all occurrences, it can potentially reduce the time GMs spend working on this issue!