What you are proposing won't solve anything, the #1 source of malware on Android is Play Store ads, here I said it.

And Google benefits financially from the problem.

Financial incentives aside, a higher assurance tier on the app store would enable me to tell my relatives "all apps that handle money or government details will always have this mark next to them" among other things. Whereas the current situation has me actively investigating moving them over to graphene.

You "saying it" doesn't make it true.