There are still many additions that can be made to this system. From the number of sensors that could be supported, further GPIO expander chips, air-conditioning system configurations, room occupancy detection linked into a calendar backend, to clearing out scheduled meetings at an office where nobody showed up, and so on.
There is also the option of switching from ESP8266 as the MCU to a different one, such as ARM-based MCUs, to get wired Ethernet options, along with better debug and development tools. As convenient as it is to have an MCU with Wi-Fi, which one can just stick anywhere and theoretically have it work, the development tools for the ESP8266 aren't that great, and the lack of wired communication options (without using external chips) means that everything either works or doesn't depending on the quality of the Wi-Fi network.
As BMaC involves the automation of a building, it is desirable to have a certain level of reliability, which is hard to guarantee with...
