Here's a suggestion: it could ASK THE USER FOR PERMISSION before KILLING ALL HIS APPLICATIONS. And how about having the uninstaller actually uninstall all the crap the installer put in there? The installer generator should make it harder for developers to make user-hostile installers.

Developers! Please, please build your installer the OSX way. Download Adium, see how they did it. Your users will thank you. If your lawyers tell you you need a clickwrap license, you can add that to the dmg file, or have it shown the first time the application is started.