I may not be answering your question since I'm talking about usability instead of more powerful features, but I can't but imagine that there'd be a market for simple and easy to use, even if it turns out it's not going to be addressed by your particular startup...
I have a table, some data that I've laid out in rows and columns. Something simple. How much money I've been paid on my invoices to clients, for example, one invoice per row.
Then I want to sum the column, to get how much I've been paid in total. (Yes, I'm talking about a very simple spreadsheet. But that's my point, that something so simple is still messed up!) So I type in a formula: =sum(C2:C10)
Now I add a row, to put in another entry. Does my sum change, to include the new row? (C2:C11) No, it does not.
So I do not want to be saying sum(C2:C10). I want to say, here is my simple table, and give me the sum of this column. Which, I don't know what the language would look like, but if I named my table "invoices" maybe it would be sum(invoices.C) or sum(invoices.amount) or something.
Every time someone comes out with a new spreadsheet (Excel, OpenOffice, Google Docs...) I look to see if it is easier to use. Nope! Everyone is too busy being compatible with the last guy.