To avoid buying a floor scrubbing robot as well as a vacuuming robot:
For example I will use a Neato brand robot vacuum cleaner.
I would like to see an added accessory/option on the robot that would allow me to switch the vacuum motor off, plug the vacuum intake hole, and replace the carpet brush
with a brush better designed to clean hardwood, tile and grouted floors. The robot could be set to clean the floor one, two or three times.
The hard floor brush would then be removed, the interior of the vacuum in front the of the vacuum hole would be cleaned, the regular brush would be replaced with the vacuum brush if need be at the moment.
A pressurized bottle of grout and floor cleaner would ride atop the robot and consistently spray the necessary amount of cleaner out in front of the robot.