I have been experimenting with this for a couple of weeks, and developed a technique to enable a user to create and color line work intuitively, without having to worry much about how well these object will animate in Synfig. I think this could allow for more complex drawings to be introduced in a project. This technique is best suited for interconnected parts, (arms, legs, clothing, etc.) while smaller, disconnected details such as facial features are probably best developed using standard techniques.
AS A WARNING: if the user decides to go with this technique, s/he will sacrifice the ability to use transformation layers such as Rotation effectively (Linked vertices get pulled apart when transformation layers are applied). The user will probably have the best luck rotating groups of vertices independantly, and mediating the in-betweens with waypoints. It sounds messy, But after trying it for several minutes, I found that manner of animation to be rather intuitive and easy.
I’m hoping you guys like this, and if you’re interested, maybe you could help me figure out more details on how to improve this technique! I know there were some recent additions to Synfig that had to do with linking vertices, so I don’t know if this technique is now obsolete. But if not, then this is another option animators could use! The tutorial is in the zip file.
EDIT: I don’t mention it in the tutorial, but it is probably a good idea to set the paths to have “no outline” and fill the background path with black. The background path’s fill will provide the outlining, and this will ensure a clean look that is no different from your original line work.
Preparing an image for Synfig With Inkscape.zip (373 KB)