These don't work for WiFi drivers as I pointed out because they're not actually the firmware, they're packages to download the firmware. That obviously doesn't work if you don't have a network connection.

No, those do contain the firmware. https://anonscm.debian.org/cgit/kernel/firmware-nonfree.git

I see that I mixed up two of my laptops in my example. You're right, but my general feature request still stands.

Yes the iwlwifi firmware in particular is shipped on the nonfree firmware CD image. But the firmware my other laptop isn't. With the stretch rc5 non-free image mounted:

    $ dpkg -c firmware/firmware-iwlwifi_20161130-3_all.deb|grep -c ucode
    46

But instead of providing the b43 firmware there's only a network installer to fetch it:

    $ ls firmware/*b43*
    firmware/firmware-b43-installer_019-3_all.deb
    firmware/firmware-b43legacy-installer_019-3_all.deb

Looking over the packages more closely now it seems only the b43 package[1] uses this approach (although there might be more firmware that's not included at all).

1. https://wiki.debian.org/bcm43xx#b43_and_b43legacy

Blame Broadcom for that; the b43 firmware may not legally be redistributed, so the only legal option is the fwcutter.

Hence my suggestion that the Debian project distribute a script that I can run to get the firmware myself & trivially build my own install CD, and that this be prominently advertised on debian.org.

The Debian project already ships that sort of script in the current non-free firmware CD, so clearly it's not a legal issue. What it doesn't ship is the ability to run that on another machine as part of preparing an ISO to install on a fresh machine that needs the proprietary firmware.