Copying and pasting a large dataset like 2000 rows and 5 columns, will take some time depending on your machine’s speed.  Improving performance would make it more user-friendly and perhaps display a loading indicator similar to Excel when pasting large amounts of data.

Provide built-in border tools for customizing the appearance of the cell borders. A similar feature is already available in the Kendo jQuery Spreadsheet:

It would be convenient each formula to have a description underneath. In this case, the user can choose the most suitable one for a certain case, without the need to know all formulas in advance.