That's a very good insight! We treat spreadsheet more like a database with a schema. What you propose is a schema-less approach. I like this idea, and I think we will try to implement it, as we see that in such solutions schema is needless and is adding more complexity for the end user, which, in most cases, don't care if there is any schema or not - she is just a spreadsheets user.

From the other hand, it's hard to map JSON to a spreadsheet, because - what to do with the nested keys. Any ideas?