Sometimes a print will have a problem area that could be improved by tweaking the GCode directly. It would be helpful to have a scroll window containing the GCode that is synchronized with the tool path display. This would allow you to locate the problem area using the tool path graphic and edit the GCode to make changes specifically in that area.
I am thinking particularly of situations where a print has steep overhangs and the wall thickness thins excessively. This could be fixed by increasing the flow rate in the area of thinning by applying modifications to the corresponding GCode. The problem is that currently there isn't a tool to aid in doing this. I recommending adding such functionality to Simplify3D and in addition allowing the GCode to be edited directly in the scroll window.