It would be nice if there was a way to allow HomeKit Controller devices to show up in HA, without compromising their HomeKit specific features.
This may include Adaptive Light, HKSV, or other manufacturer specific features offered by VOCOLinc, door locks, etc.
The existing implementation for HKC would continue to function as they do today in HA, by pairing with these devices and creating devices/entities in HA. Instead of re-exposing them through the HomeKit integration, it would be even better to offer up a simple HomeKit Proxy to be paired that uses the same pairing code as the original accessory to create a near seamless connection to the original accessory. Obviously, the pairing would be handled by HA (or the integration) since the device will have already been paired, but the services, characteristics, etc requests would be passed to the accessory and delivered directly to the iOS device without needing HA entities, states, etc.
Ideally, a bridge accessory would remain a bridge accessory, and a standalone accessory would remain a standalone accessory. Truly a 1:1 proxy. It would be nice to have this as an opt-in feature in the existing HKC integration in HA and it seemingly would not rely on the HomeKit integration at all. It’s also possible this would be an entirely new integration in HA, and would interface with HKC.
This repository is a little bit of the inspiration GitHub - Supereg/hap-proxy: Transparent Proxy for the HomeKit Accessory Protocol to intercept and analyze traffic between an Accessory and an iDevice.