That was yes in favor of merging as is. Unless there is a big win to hide the details behind a config option (e.g. how to manage our current version of update_engine or locksmith is kinda a coreos implementation detail and may change) I'd favor documenting generic ways to tweak things so it is easy for users to apply it to other things.

A special cloud-config option could be useful for specifying a proxy for docker, update_engine (once it is supported), and others all at once.