This plugin has only ever intended as a stop-gap until WordPress properly resolves the lack of notifications for removed plugin, so this isn’t a great idea for a plugin since everyone should be notified when they are using plugins that have been removed from the Plugin Directory for security issues instead of just those that happen to use a plugin. Otherwise websites are going to continue to be hacked when those hackings could have been prevented by WordPress acting responsibly.
Seeing as this plugin only provides a limited version of the needed functionality, it would make more sense for the issue to finally be properly resolved by WordPress and then plugins (whether new or existing) could provide an email alert based on that, instead of adding more functionality to a plugin that shouldn’t have needed to exist in the first place.
