The Screen Lock on Android phones has been a point of contention for me for years. The only alternative I've discovered is to us a Tasker plugin called Secure Settings, which has an option to enter a PIN/Pass, or to clear the PIN/Pass.
Are there not specific intents available to allow direct change of the screen lock type, i.e. None, Slide, PIN, Password, etc? Basically, a better, conditional-based means of Google's Smart Lock feature.