Just finding out about Lotus Improv, which is exactly the kind of spreadsheet design I've been saying for years we should have, yet it failed to gain any adoption, being fully killed in 1996. Reminds me a bit of Resolver One, which was killed in 2012.
I wish we had a spreadsheet today that leaned heavily into structured data, effectively an interactive UI for SQL tables, but much easy to create and modify. But the consensus seems to be that such a thing dies at the hands of "worse is better".

Now we live in a world where free-form Excel spreadsheets *can* have some structure imposed on them, but that rarely do, instead of one where structure is the default, but with free-form sheets available.

I guess it is the dynamic vs static typing argument all over again, but playing out on a field where people don't necessarily see themselves as programmers.

@ekuber it's a bit like Microsoft Word vs LaTeX.
Wysiwyg hacks vs structured document.
Yes you can structure your Word document and use stylesheets. But you don't have to either.

(applies to LibreOffice an most other consumer grade word processors)