In order to customize who receives email notifications for a specific email, we much customize the email itself. If we aren't making any changes to the default email, it is still treated as a customized email. I assume this means that if features are added to the default email notifications they are not applied to the customized emails. This is a pain, as many of our emails are not really customized, they are just being sent to different users.
I propose a separate section to assign who received the notifications vs a combined screen that both customizes the emails and assigns users.