Congrats on the alpha, that's always an exciting time. Given this is an open source project, I think some clearer documentation about the system architecture and components would be a great improvement. I'd also want to know up front where my assets are being processed. I had to dig into the code a bit to find the imagga tagging functionality. Some users may feel uncomfortable uploading assets to a third party if you're not absolutely up front about where the data is being sent. I'm curious about the built in CDN, so documentation on that would help me make an informed decision on using this product.
Never assume that your audience knows anything of real substance about your talk. You've spent many hours building up knowledge and context about the subject, and your audience is coming in cold. I've rarely been to a talk where the speaker "over explained" the material.