I think a good feature would be the option to have different layer height for the outline perimeters in relation to infill layer height (smallest layer height prints first until they reach out the thicker layer height, then thicker layer gets printed). This way you can have perfect surface while reducing print time from the infill height.
You can already do this. Just set the layer height to something like 0.1mm, then go to the infill tab and tell it to print the infill every 2 layers. Then it will print 2x 0.1mm outlines with a single 0.2mm infill layer.