It would be killer to be able to just draw something freehand AS a token. The time it takes to procure tokens is a bit of a drag, especially for random encounters. Being able to just draw numbers, freehand, would be awesome.
In general, I'm not a fan of lifelike tokens or detailed artistry. Rough lines, numbers, etc., are more my style. I find that preserves the imagination quality of pen and paper gaming, and avoids the tendency for this tool to feel like a slow video game.