Re: Solution
There's already a specific Android permission for this "Draw Over Other Apps". Thing is, like the article says, some apps need this functionality to interrupt user action. What's to stop this function being used for evil while at the same time being disguised as something plausible like an alarm clock?
Sounds to me like the most robust way to handle this (separate the desktop compositor into a black box task and let the apps request their graphical resources from that) has drawbacks of its own such as memory and CPU/GPU costs.
Biting the hand that feeds IT
