One of the goals of this release is to remove this fragmentation. For example Docker Cloud will use CE, and soon will allow you to easily upgrade to EE.
In the free / open-source side, Docker CE is the "one core to rule them all" that you describe.
I just didn't wanted to have different daemons (server, not client), and having to replace them if I'll want to use Cloud, EE or whatever (or stop using that or replace them with something else, etc).
In the free / open-source side, Docker CE is the "one core to rule them all" that you describe.