When you export a cell or screen and in the chosen location is already a file with the same name, the export dialog provides the following possibilities: Stop, Skip and Replace.
Stop: I would prefer "Cancel" here
Skip: This button is even enabled if you just want to export a single item and in this special case it does nothing else than the "Stop" button
Replace: This one is fine.
For now I'm missing an additional button called "Keep both", just like if you move elements in Finder. If you choose this option, the new item's title will be appended with a simple " copy".
In the current version of the dialog you have to go back, start the export again, rename the items and proceed. That's really annoying, particularly if you do this several times a day.
I would like to just click on an existing element in the dialog's file browser in order to rename the currently selected element in the export list. As shown in the screenshot, the screen being exported should be saved under the same name as the image in the file browser above.