Actually I've tried to start a discussion about this topic on the "network" forum, but maybe it wasn't the right place, so I try to write it here.
Here is the suggestion: I've found a very clever mechanism implemented for ESP8266 devices to let their users to easily connect to a new wireless network. It's a library called wifimanager, you could easily find it on GitHub. They way it works is rather brilliant actually.
When the ESP8266 starts it tries to connect to a wireless network with the information stored in the program code. If it doesn't succeed, it turns into AP mode, creates an open wireless network. At this point the user can easily connect to this network and through the captive portal, hosted on the ESP8266 device, he can select his home network from the ones discovered by the board, insert the correct credentials and at this point the device reboots and connect to the wifi network.
I find this behaviour very smart and convenient for an headless device, such a typical IOT project that could be implemented even with a PI ZERO W for instance.
Would it be difficult to implement such behaviour on RASPBIAN? Actually I think it's so clever that it deserves to be considered as a default mechanism for wifi set up. If a simple (relatively) device like the ESP8266 is able to do it, it should be possible for the PI.
I would really love to contact someone from the RASPBIAN development team and suggest to implement it, or discuss about this possibility.