Just a simple button or option on the entry screen, that will export to a simple text file the complete inventories, backpacks, bank contents, TR cache, shared bank, every bag contents, absolutely everything that is anywhere.

The exported data doesn't need to look pretty, just plain old text will be perfect.
And then leave it up to the players to prettify it.

I have 14 or so characters and been playing around 5 years. Several characters TR'd. I probably regularly play about 8 of my characters, I have bought MANY additional bank and backpack slots to 'store' BtA, BtC, or useful sounding stuff, ...

Why:

I'm sure somewhere, one of my characters has a <insert name> this is important because I just got <insert other name> and if you put the two together they are much more worthwhile than having just one of them.
Or
I finally got shard/seal/scroll, and now I can't find the item they go with <doh>!! lol.
Or
I need XX of <insert name> and I must have at least that many if only I knew which bags on which characters they were in.

You get the picture I am sure.

I have several methods to try to help me organise my stuff, including bags in my shared bank one each for seals/scrolls/shards, plus other bags with shroud materials, Cannith materials, etc. etc. etc.

A quick, simple and dirty export function would be "awesome".