Virtually every MMO player in every MMO game eventually creates a mule character. A mule is a character in the game that doesn’t fight or adventure, it just holds stuff for the active characters of that player. The mule takes up a character slot and it cannot be accessed while logged on with any other character.
So why not just make a Mule class/race (Mule with a capital “M”)? Give it inventory spaces equal to the maximum allowable bank slot space (after the requisite favor) PLUS maximum allowable backpack space (after the requisite favor).
A Mule would basically be a portable bank companion.
Mules can:
Be logged on and controlled simultaneously with any one other character of the player
Carry items
Trade items with any character of the player
Go anywhere in public instances
Run fast
Wear/Wield/Equip any item (so you can see what it looks like)
Mules cannot:
Enter Quests
Talk
Trade with anyone other than a character of their player
Fight
Have a Bank Account
Use any item
Cast spells
Sure, you can argue that people will still make mules out of their lesser used characters.
Sure, you can argue that plat farmers will mistreat their Mules.
Sure, you can argue that we already have banks slots, extra inventory slots and soon gem/collectable pouches.
But I believe most players would use their Mule. Mules don’t need to level or get favor to gain extra space. They don’t get quest invites while doing their job. It saves the player from logging in and out of multiple characters to find that one misplaced item. And I really think most people would probably decide that if they can’t store that extra item on their Mule, they don’t need it.
Look, just because your elf fighter-wizard named Drizzit1234599 was a terrible build (and created before you unlocked the Drow) doesn’t mean he should be kept alive as a virtual garage. He was once your favorite. He fought and died for you time and time again. Let him finally die in peace.
Kill the mules. Add Mules.