Freehand sketch?
 

First off, thanks for this amazingly useful app! I was a bit disappointed with version 1, but the 1.1 update was a dramatic improvement. I'm excited to see how it will grow from here.

Speaking of future growth, do you have any plans to include a sketch tool? I love the current freehand shape tool, as it frees me from having to think about tool selection while brainstorming something. But I also find myself while in this mode of thinking wanting to write a quick note, or to label one of my figures. It would be great if I could just write it by hand. Ideally, one could switch from freehand shape mode to freehand sketch mode with a simple gesture, like a three finger tap.

I realize I can add a label to a shape just by double tapping on it, but I find that the sudden appearance of the keyboard and having the drawing shift in the view is enough of a disruption to break my concentration.

I have mentioned this somewhere else already: I believe an Instaviz like function (drawing circles yields a circle, connecting two circles yields a line inbetween etc.) would make it a killer app for a lot of computer science people like me.