Hi devs! Here are a very tiny and basic branch ready for review. With it you can smooth pencil strokes with the slider at any moment.

https://code.launchpad.net/~inkscape.dev/inkscape/simplify-lpe-pencil -toolbar/+merge/252223

Cam'on is only 219 lines most of them svg from a new icon!

A video working: https://www.youtube.com/watch?v=xDef4hU4tNc