It would be nice to be able to mark a volume where the print head does not cross.
This would allow for the placement of objects that can be trapped inside the print with a portion of the object protruding from the print, such as a metal bolt.
It would be nice to be able to assign a status of pre-exiting to the object and then have the print head navigate around that object.
Taking this idea a step further - Collision detection would be great. A user could import and STL of the print head with the origin of the STL file located a the nozzle tip, and then Simplify3D could use the print head to check for collisions between the parts and the head. This would allow for much more robust sequential printing.