I agree with what you're saying, but I'm not going to be pessimistic about the endeavour! I think, given time, we can build something that solves at least some use cases better than Calc.

Libreoffice hacker here. Calc is one of the nicer parts of the codebase. Don’t underestimate the enormous list of features that are required in a modern spreadsheet engine. We’re talking 100s of man-years of coding. Come join us and make it better. Or task one of the available consultancies to implement the features you want.

I know I am underestimating; I have a tendency to do that, so I appreciate the warning. May I ask how many people currently contribute to LibreOffice regularly?

There are about 20 people or so who contribute on a frequent basis i.e. at least weekly.

But we have a very long tail of people who contribute less often.

You can see the commit frequency here: http://cgit.freedesktop.org/libreoffice/core/log/

Come hang out on the libreoffice-dev IRC channel if you have more questions