If possible, a new screen which shows a breakdown of each city's tiles would be really cool in getting an overview of where your Worker units are most needed.
Useful information on this screen would include the following information about each city's usable radius (within its cultural boundaries):
# Land tiles
# Water tiles
# Improved Land tiles
# Unimproved land tiles
# Land resource tiles
# Water resource tiles
# Unconnected land resource tiles
# Unconnected water resource tiles
This shouldn't be too hard to add to the CDA as a new set of columns.