> I think modularity is really key here. As long as you can replace or update each component individually without impacting the rest of it, you should be good.
That's exactly it: the ability to easily swap out components, and then high levels of interoperability. I think I perhaps didn't express myself so well because I'm broadly in agreement with you. It's the phone home aspect that often makes smart devices a problem.
I have a similar but marginally more lax policy: I'm fine with smart devices as long as they don't have to phone home to operate and they have on-device controls.
For obviously Internet of Shit-worthy appliances (Cory Doctorow's smart toaster or whatever) I'll always choose the dumb version, and I make sure that I only use home automation stuff that's as widely interoperable as possible, but otherwise I don't particularly fuss about it as long as it meets all of my other requirements.
I think modularity is really key here. As long as you can replace or update each component individually without impacting the rest of it, you should be good.