When using the paintbrush tool you get to see a preview of the stroke while drawing. The pencil brush only shows the center line rather than the whole stroke that's being drawn, but I would like to see it while drawing the same way paint brush displays it.
Before you tell me to just use the paintbrush, I prefer a pencil mainly because it defaults to basic lines rather than the non-uniform calligraphy brushes. If I could use the paintbrush as basic stroke I would just do that but instead, I have to go in afterward with lines selected and change them to basic which is kind of a hassle when you want to work fast and across layers.