1. A new format would probably be okay, but make the icon for the application green so it looks like an excel file. It can open excel files right?

2. A lot of our sheets use VB/macros so a scripting language is pretty useful. Not sure about the other stuff.

3. No idea, around the price for an office 365 seat?

XLSX is an open format, why invent another? xkcd 927

python in the app needs to be wholly self contained so whatever the backend it uses, it's separate from anything else on the system.

charge through the nose for desktop clients because of how much it costs in development and support time. people who want native clients so it's not up on a cloud somewhere for whatever reason can pay for that privilege.

I live in excel in a multibillion dollar company as the "excel" guru... though my company doesn't really have big data generally speaking

I would love a performant desktop excel replacement - I miss using excel 2003 - it has been downhill ever since...

That said, I'm clearly not the target market for this product though I believe there's some degree of frustration with how poorly modern excel works with many files now which this product may address.

I would guess that making this a light-weight and performant (not electron) desktop app (ideally portable so installing it wouldn't require admin access) with substantial feature parity and compatibility with excel would be a big deal - I'd install it right away...