Since these will all be Thunderbolt/USB connections, even HDMI/DP would be a dongle, the port numbers would be enumerated on wake, and therefore shuffled.
> when using a bluetooth headset, where suddenly you hear someone elses conversation because you have the same MAC adress.
That's not something I would have expected! I thought that both sides had to handshake. Just having a MAC address conflict wouldn't mean that the headset listens, does it? That's mad!
Apple decided that the correct way for them was to use the display unique identifier, which unfortunately for budget displays is not unique.
That is the fundamental problem here.
You are now arguing from the position of someone who is trying to make the system usable under more scenarios, while Apple doesn't care if your 3rd party equipment doesn't work. The child here is the monitor manufacturer, and you should have bought good equipment in the first place.
It's like complaining about their half arsed HiDpi scaling options. If you had bought a monitor that had the correct pixel count for the size of the screen then it wouldn't be an issue in the first place.