I think you misunderstood. I never said Docker sucks. I said there are ways to handle various kernel+distro combinations with Docker just by having various hosts that runs those kernel+distro combinations, that was in defense of LXC.

I haven't used Docker yet, I am only familiar with LXC so far so I was commenting on that. If one does have a uniform or a restricted set of platforms that can also act as LXC hosts then well why not take it and run with it. It is more efficient and that might translate into performance and cost savings.