Is it likely that in future updates we'll be able to export brushes to Illustrator Draw on the iPad?
Yes, we are looking to support Illustrator-style brushes in Illustrator Draw in a future update.
More Adobe Brush Feature Requests -
Love what I'm able to do with a phone camera and Adobe Brush capturing shapes, textures and patterns in the world and bringing them into Adobe Brush!
-Another request for future releases is support for creating Illustrator pattern brushes. I know from working with Libraries that if you save an object with a created brush the brush (all appearances) are remembered when the object is stored in the library. I'd like to see brushes and patterns be saved, perhaps in some way using graphic styles and save those independently in the Libraries. In other words, I would be able to save all of my brushes, created in Illustrator, Photoshop, or Draw in Libraries for workflow and archiving.