Home automation is, by the nature of it, a series of distinct functions spread throughout the home (e.g. front door lock, garage control, temperature control, lights in each room, sprinkler system, washer/dryer alerts, etc); so you're going to need each of these geographically separate things communicating into a central control "hub."
You cannot physically move these things into a module on the central control hub. Most of them have to be in the location they're already at (e.g. physically in the front door).
How does making the control hub a modular unit help with the complexity of home automation? If anything it further adds to the complexity. A lot of the solutions now just use WiFi networking and a standard protocol.
I'm just not understanding your concept at all.