Flynn still needs to do a much better job on the documentation front. It's entirely unclear how to use Flynn. Instead of just having vague architecture/philosophy discussions, they need very clear explanations.

From the demo/documentation they do have, it's unclear why Flynn is better than Deis, Heroku, etc.[1]

I had hoped that Flynn was/would be a tool for orchestrating complicated multi-container apps, not just deploying Procfiles. I don't need Procfiles, I need something which will let me integrate and orchestrate multiple Docker containers across multiple nodes. Most/many significant apps don't fit into the simplicity of Procfiles (we have over a dozen different services, some with relatively customize environments, all communicating with RabbitMQ middleware). At least for development, Docker containers have proven to be an ideal way to manage these services. As of yet, there doesn't seem to be a good tool for deploying them to production. I wish Flynn would tackle that head on (and document it!), instead of being yet another generic PaaS.

[1] https://github.com/flynn/flynn/tree/master/demo