Hey piac,
thanks for your reply and even more thanks for your plugin! 
In the end it’s mostly a cumulative effect. I ran against more and more performance walls and one major job at the end of august this year made it clear that if I want to follow this line of work further, I need much more “headroom” in what I can handle. At one point during that job I had a Rhino file that was over a gigabyte of baked GH mesh data. Rhino took ages to save and load it, chocked on displaying it and bluescreened on rendering.
I had to convince my customer to take a different approach.
It worked out in the end but afterwards it became clear that this isn’t sustainable.
I looked at the Shortest Walk code myself but it was a bit over my head. I think introducing ways to guide the directions would be extremely useful. If you check these: https://www.screendream.de/design/life-love/ you can see that it would be very nice to have something like guiding splines or weights to be able to define paths that don’t cling to the borders like in the “LIFE” letters but keep to the centre more.
And just to make that clear: I totally love GH and your plugin saw a lot of use here. It’s really awesome work and got me going in this whole direction. I know that version 2 will have multithreading and that alone should solve a lot of problems. If things don’t absolutely have to be baked, that will also help.
Cheers,
Tom