Photoshop: When sketching over existing lines, gradually erase lines drawn earlier automatically

This is a good idea, one that would probably have better success in an iPad app. Adobe hasn't put much focus into hand-drawing/painting for some time.

> The next step would be to use machine learning to analyse the users corrections in lines and to correct them realtime while one makes a sketch. Have you considered experimenting with this kind of data driven sketch software? >

Interesting idea for a pixel-based program. Currently it's available in vector, since vector does know mathematically precisely where a path is drawn and can easily redraw it to fit the next stroke. Although Illustrator's Pencil tool can do this, making drawing and editing the drawn path at the same time feel very intuitive to analog sketchers, Astute Graphics' Dynamic Sketch is even better (a plug-in for AI). From there, it's an easy process to take the sketch into PS for whatever else you want to do with it.

I personally doubt PS is likely to take this up anytime soon for their pencil/brush tools, but you never know. They seem very interested in developing their Sensei features as fast as possible—or they might bring it in as vector freehand drawing, although if you can't "stroke" the path with a simulated real pencil, it wouldn't be very wonderful, so you'd need to be able to apply a brush tip to the strokes.

Nice and spectacular idea, but like Cristen mentions - good understanding of vector/beziercurves makes sketching less urgent. My favourite way to work with sketches, is to make those on paper, scan or photograph the paper and then draw bezier paths on top (in Ai).