It will be interesting to see how much of this relies on the presence of existing hard wired systems, many of which are controllable over the network (e.g. Lutron, many security systems, etc). Writing to other peoples' APIs has not typically been Apple's strong suit. At the same time, wired-in infrastructure in a home is nothing like as disposable as the consumer technology Apple focuses on. There is no way I would want a closed system baked into my house. Hard-wired infrastructure is something you're stuck with for decades.

Relevant to me as I'm in the rough-in phase of a whole-home remodel project. I struggled a lot with what level of control to use, before settling on a minimal Lutron system for some areas of the house, comfortable in the knowledge that if I get tired of the Lutron interface, I can create my own & poke it over the network. I understand most people aren't interested in this level of control, but they might be concerned when their interface becomes dated in 5 years and can't be replaced due to an incompatibility with the hard-wired infrastructure. I see this as a downside of closed systems like Control4.