I'd like to see an option for a single layer line font on the top surfaces. like lettering on a cake. it would be nice for very small lettering, signatures, and custom graphics. For example, I regularly print parts that require ID numbers. I print them at .4 layer height for speed and strength. For some, the only area I can add text without compromising structural integrity is so small the text is unreadable, and adding text to the vertical surfaces either weakens the part or causes unacceptable surface defects.
I like that idea, but it borders adding modeling features to a slicing program - and geometry creation is a whole different animal from slicing. From a feature standpoint, perhaps it could be handled as a way to handle single-layer geometry so it does not impact the underlying infill pattern. It's probably a possibility now if one uses multiple models and processes along with the newer thin-wall handling.