What I want out of a "smart" switch is that it exposes an API over a network connection for what it can do (turn on, off and maybe dim the lights) along with a Unique Identifier of some kind. CPU and network stack all running on a Harvard Architecture system with no possibility of upgrade.

The "smartness" should come from a device (be it a smartphone, hub-like device like an echo or my router) that maintains the mapping between device addresses, api and friendly names. That can be upgraded, replaced, exposed to the outside internet.