It's not like the first-gen devices have killswitches.
Killswitches are iOS 4-only apps, which (based on experience with iPod touch) will show up in AppStore, but you will not able to install them. Also, you cannot get previous versions (3.x-compatible) of applications from AppStore.
That actually can make the experience worse. For example, if you decide to use the iPhone with a different AppStore account. There's no way to get back the versions of apps that work with the old version of OS.
Killswitches are iOS 4-only apps, which (based on experience with iPod touch) will show up in AppStore, but you will not able to install them. Also, you cannot get previous versions (3.x-compatible) of applications from AppStore.