Not a PowerApps idea but a PowerUsers Community for PowerApps idea.
Think about it. Most of the people in this community are here to ask questions about their problems regarding PowerApps and most of them are essentially repeats. For instance, for the past week (I've been bored), I've seen the following questions asked repeatedly:
Simulating table join operations using the in operator or the AddColumns() function.
Referencing and using look-up values from Sharepoint.
Working with Sharepoint look-up values and Dropdowns. (Seriously, what's the point of the abstraction with connectors when you're going to have to make connector-specific fixes anyway)
Ways of exiting the app using Launch() and Exit()
How to use the apparently mysterious Patch() function.
Having a FAQ section that's only controlled and managed by PA Staff / Community Moderators for QC would be great. Users can suggest posts they think should be in FAQ and the Community UI can bring it into attention. Got a serious bug in the latest release? Put it there. Got a commonly known limitation of PA? Put it there.