If anything you're underselling the existing hurdles. It was once thought that the brain was immunoprivileged, but now it's known to have its own immune system.

If anything you're underselling the existing hurdles. It was once thought that the brain was immunoprivileged, but now it's known to have its own immune system. As a result implants are prone to having scar tissue form around them, and after some years it starts to inhibit their ability to perform.