Great post! You brought up some really interesting problems with current mobile UX designs. I especially liked your point about the onboarding process. This is one of the most important stages in the app lifecycle. A bad onboarding process can make or break an app’s success.
I liked the alternative solutions you offered. I think you gave a nice example of Slacks onboarding process and the benefits of using this process instead of an overlay. One way to see if these UX changes are working is with qualitative analytics. You can watch actual user session recordings and touch heatmaps to see how users are interacting with your app. A great tool that can do this is Appsee.
If you’d like to learn more about Appsee feel free to contact me at email@example.com.