Earlier quoted context omitted.
All of that is already accounted for and protected by in the OS. An app cannot normally register daemons or agent (or even an XPC service). Installing is already limited to FrontBoard standard installation mechanism. All that will remain in a possible open iOS future.
Except usage of private APIs?
https://github.com/LeoNatan/LNExtensionExecutor
This is a framework I obfuscate API usage, and is present in several App Store apps that I know of.
Apple security comes from kernel hardening, not static API analysis.