This is something we have planned to build, a dev tool with a developer dashboard consisting of some essential metrics about the app to better understand the app performance and usage to do improvements.
This is in our roadmap and we will pass your request as well to our engineering team to prioritize it.
We will let you and the community know when it is launched soon.
Agreed with @shravan.balasubraman, as an App Development company we are facing roadblocks in decision making for our Paid APP Twilio Plus
due to unavailability of performance data
Glad to know that you’re working on app performance metrics; Hope will get it soon