Security is good, but it isn't a big problem for my current local container apps. However, I've found Docker clumsy in various areas. Does this improve on the design any?
Also, is there a PPA planned for Ubuntu, or plans to get it into Debian soon, now that it has reached 1.0?
I can only speak for myself, but for me it does, by forcing you to do stuff differently.
Eventually you realise that Dockerfiles are fine and dandy, but this mechanism isn't really needed and it can be an obstacle. You realise that a good package manager is your real friend. So now I use wonderful xbps-install from Void Linux to create a complete rootfs + actool to make an ACI file and that's it. A basic webserver can work as a repo for your xbps packages and your ACI images. No need to use Docker Hub or Quay, etc.
Also, is there a PPA planned for Ubuntu, or plans to get it into Debian soon, now that it has reached 1.0?