We're definitely thinking along the same lines. I agree entirely about many small spreadsheets and the like. Another inspiration for me here is the long-lost Lotus Improv, which instead of being a blank page was more like a table, with explicit, named rows and columns. For me a general principle is to look at what people mostly do with spreadsheets and make explicit support for that.
You're very right that choosing the right language is important. As much as I love the languages I know, most of them are incredibly fiddly. E.g., things like dealing with "if a=b" are fine for those of us steeped in the mysteries, but a nightmare for more casual users. I'll have to check Julia out. Thanks for mentioning it!
There was also something called "Framework" that went a bit farther than spreadsheets. Of course when I write Spreadsheet here I mean "Spreadsheet products available in the 80s": https://en.wikipedia.org/wiki/Framework_(office_suite)
You're very right that choosing the right language is important. As much as I love the languages I know, most of them are incredibly fiddly. E.g., things like dealing with "if a=b" are fine for those of us steeped in the mysteries, but a nightmare for more casual users. I'll have to check Julia out. Thanks for mentioning it!