Oooh thanks for the tag @Peter_G
Many opinions on the topic - I even posted something about it way back after playing with it for a bit - although some of the things since then have probably changed:
But my new version of things would be something like this:
A truly "total" view of my Monzo account in the export, with rich data and meaningful meta data.
- What I mean by this is literally any and all movement of money within my Monzo account to be captured as a line in the Google Sheets / CSV export.
- Currently, only “Main Feed” things are captured; wasn’t too much of a problem initially, but now with Flex and with Virtual Pay from Pot - I am losing data. As of today, I can’t see Pot Transactions w/ V Card, Interest in Pots, Flex.
- Total View - by that I mean - treat it as a ledger - If I send money to a Pot - I’d like to see both sides of that movement occur; when I buy something on Flex, I want to see my Flex pot money owed go up.
- Rich Data - I want meaningful data, in a consistent way: the best example of this is how Flex Payments show up; I can’t tie that info back to anything in my Export - I’d love to see references to unique ID’s etc - when they are known. The consistent part is how “notes” are used - currently rich useful info is hidden in their and I’d like to to be more systematic in the data.
Future Proof the Export, and make it compatible with future changes.
(Alternative: Design it with a users goals in mind)- In essence, every time a new feature comes out, it means I lose some data, or otherwise can’t see my total balance.
- Things like “Type” for transaction is somewhat inconsistent - has what is obviously useful internal meta data like “bridge transaction”, “premium_subscription”, “monzo_paid” etc - which don’t really “do much” for data use - and a little bit annoying when trying to filter and categorise things.
- Equally, as new features come out - i’d like them to work in the sheet too; I’d like to be able to see thigns like which virtual card is used, and other connected data types that currently don’t exist.
- Another one is how split categories are handled - I’d love to see that as multiple entries for data analysis rather than the current mechanism.
Publish some "Dashboard Templates" to help people use the data.
- What it says on the tin really, but yeah, If you’ve not read “The Life Changing Magic of Dashboards” then I thoroughly recommend it
I know there’s a lot in that - and happy to expand on any of it.
My last thing though would be - Make sure the data is an accurate “Version of the Truth” - and by that I mean, I should be able to trust that when I calculate my account balance, the number is accurate. Right now I can’t do that. That would be my primary goal.
Merci 
Edit: Conscious I’m treating both CSV and Google Sheets exports as the same topic - I know they are functionally different but I think they should reflect the same data so