"- Bundling-in the orchestration with docker make k8s or Mesos more inclined to fork docker and pull out unnecessary cruft."

Mesos 1.0 already introduced the universal containerizer, allowing to run many docker images natively without the docker daemon:

https://www.youtube.com/watch?v=rHUngcGgzVM&index=14&list=PL...

http://mesos.apache.org/documentation/container-image/