I would like to be able to do conditional formatting against other columns and not just the existing conditional formatting.

For example:

Column 1 = 1.2
Column 2 = 1.5

If the value of Column 2 is greater than the value of Column 1, I want the color to be green.
If the value of Column 2 is less than the value of Column 1, I want the color to be red.
If the value of Column 2 is equal to the value of Column 1, I want the color to be black.

I know it seems like a small thing, but I work with complex spreadsheets, and supporting coloured sheet tabs would really help 
Love this control.

Integration of the pivot control with the spreadsheet

Show/Hide Column & Row Header

add a double line border single or multiple cell.

Add a watermark in each worksheet.

Please support Excel formulas copy and paste to Kendo Spreadsheet.

Now is the copy only the text, not formulas.

Spreadsheet import currently handles (keeps) rich text formatting of a cell if the entire cell is formatted, such as a colored row or all bold text in cell. However, if the content of the cell is a mix of plain text and formatted text, the formatting gets dropped on import. If it is possible, it would be nice to keep rich text under this condition.

Currently the API is very much limited to what is possible in the frontend in my opinion. It would be great if you could add events like:
- A cell/range was selected
- A cell was cut/pasted/copied
- The context menu was initialized
- A row/column was added
- A row was added/deleted/hidden
- A cell's content was modified
...
...

It would be great if you could put images to cells using html. E.g.: <img src="..."> would result in an image in the cell.

It would be great if there is a cell (and column) type that lets you choose from a defined list (manually defined list or based on a cell-range). It should be possible to make multple selections and the output should be put into the cell separated with semi-colons.

It should be possible to define cell types (or types that are valid for the entire column) like:
- Booleans (which will result in showing check boxes inside the cells)

The Spreadsheet widget is a good start, here are some additional ideas:

1) Ability to assign specific data columns to a spreadsheet column in DataSource data binding and format them.
	2) Control tools that can be visible in the toolbar as well as add custom toolbar items/tabs
	3) Enabled/Disable or Show/Hide tabs in tool bar. Alternatively, be able to add custom tabs and toolbar items as well.
	4) Events! need more events. Cell selected, Range selected, column selected, etc...
	5) Disable/Enable certain commands (such as Cut, Copy, Paste, Delete) based on #4 or other criteria. Useful if I do not want specific cell or column data copied or deleted.

I want to be able to double click a column header  to set column width to max width of entries - autoresize

Hide or disable Icons, Panes / Functions in the Toolbar

like this: http://docs.handsontable.com/0.18.0/demo-grouping-and-ungrouping.html

Somtimes you just want to give the User a little Side Calc without a full blown Sheet, just the grid with some cells able to change.

Set Fixed Cols/Rows etc. or setOptions( {filter: { ref: "A3:G49", columns:[]}});