Speaking of undo, while the 20-line limit is understandable, I'd love to have a larger buffer. Even 20 lines aren't many when you're sketching with the pencil tool, especially if you want to experiment with different ways of coloring or outlining. (At the very least, I'd love to see an eraser with some opacity to it, or a way to duplicate sketches.)

When you're done with a drawing, Paper offers a few of the most popular options for sharing it--Tumblr, Facebook, Twitter, or email--but it neglects to provide the simplest one: Export to Camera Roll. If you want to do that, you need to snap a screenshot when the sketch is full-sized.

Paper's flaws are especially frustrating, because the app is otherwise so promising. There are parts of it I absolutely love. But until Paper gets a serious upgrade, I can't see it becoming my go-to sketching app.