A common issue for me which S3D for example does not handle either is supporting Surface borders within coarse infill. While printing lightweight fairly complex structures this would be an amazing feature, i think.
My example Shows a coarsely filled benchy which would print Pretty much awful, because trying to print the shown first Surface layer would result in drooping Filament into the infill voids resulting in holes within the surface.
To Prevent something like this it would be awesome to “support” such Surface borders.
Either modifying the infill Patterns to account for incoming top surfaces or Building additional support infill structures would be two ways to attack this issue in my opinion.
Alternatively modifying infill denity below surfaces like cura does is also an Option of Course.