At this point I think it is unlikely I will continue the project. But if I did, here’s what I could do:

Blinds for discontinuous patterns.

Let's say I wanted to make a smiley face pattern. It would require the laser to turn on and off to keep the eyes separate from the mouth. The current system would not allow that because it can only trace continuous patterns. One way to allow that would be to add a blind wheel to one of the cams. This would spin with the cam and block the lasers light for part of the pattern.

Motor driven

Although against the original spirit of the project, I could achieve much cleaner patterns with more input power. This would also eliminate the need for the input crank and gear ration since the motor could drive the cam directly.

Web service for new cam creation

I already made the open source Go program that can generate cam profiles. That said, it is far from user friendly. I could foresee a user interface that allowed users to draw a pattern and click submit, and I return the 2 stl files to print.