Full functionality with Excel for iPad
I'd like to see the full version of Office (Word, Excel, PowerPoint) for iPad. The mobile version doesn't cut it, and I have to switch back to my Mac. The iPad Pro's more than capable of handling the full software.
Sean Terry commented
Bottom line. Excel for iPad is an excellent iOS spreadsheet app. The touch UI is well thought out, and support for the full set of functions from the desktop apps means you can work on even complicated workbooks while away from your computer.