Haunted by ancient history

All of that already exists. If you're running wpa_supplicant, you can never have any of these problems [even with wext, since wpa_supplicant is smarter than the average user]

However, if you're not running wpa_supplicant, then it really only leaves the kernel to remember it, or the user to re-enter it every time. iwconfig/wext went with the former (and in turn got all the associated problems), iw/nl80211 went with the latter to avoid those problems.