Great article! You addressed a very relevant topic for mobile design. Every detail matters when it comes to mobile UX. I especially liked your point about taking advantage of blank states. Your suggestions of using it as an onboarding opportunity or helping hand are great ideas!
To make sure these screens are performing the way you intended PMs can use qualitative analytics. They can watch user session recordings and touch heatmaps to see how users are actually interacting with their app. A great tool that can help with this is http://appsee.com.
Would love to hear your thoughts!