Sorry for taking so long to respond: You can pull a graphic from Illustrator into Draw, as long as it's saved to your CC Files, but only as a photo layer. It won't be an editable graphic as Shapes from Capture CC are.
This is a request that I see frequently and I hope at some point the feature will make its way into the app. I'll pass your comments along to the Draw team (along with the comments from your other post: The specified item was not found.
While it's the correct answer, it's not the one I'd like to hear. It seems like it would be pretty straightforward to share an existing AI file and utilize it into Draw. I guess it just needs time to work it's way there.
If it's any consolation... you're not alone in that sentiment.