All the praises and salutations to Serif for marvelous software.
From my point of view, editing paths (curves) while drawing with pencil tool is a must! In the same category, editing the drawing sensibility (fidelity) goes hand-to-hand with that request.
In conclusion, it is not possible to illustrate organic (complex) shapes without editing the path.
Below are the examples of my work from Illustrator. I had to edit the illustration tens of times before reaching the final shape. Needles to say, it wouldn't be possible without editing the selected path.