- When editing the sheet name in the left panel, I could drag the sheet's location into it's text field.

- Would it be possible to edit the sheet title when clicking on the title itself (in the right panel)? Maybe show a pencil indicating this possibility.

- Local time format is not reflected in the sheet's modification time. What will happen if I share the sheet, will it reflect the latest modification time for all users or my latest modification / view? What I am trying to say is: is there a way for me to see if there are changes I have not seen?

- A little bit of hierarchy or tagging might help those with lots of sheets in the future.

- Exporting and printing options? :)