You need feedback. It doesn’t matter how good your process is to start off with. You need feedback on what’s working and what isn’t. With feedback you can continually improve. Without feedback you are either shooting in the dark, or sticking with a process that will, inevitably, become outdated. Collecting, and acting on feedback is more relevant than how effective your process is to start off with.
That’s why feedback is the single most important aspect of any project portfolio management system. Are you getting enough feedback, and what are you doing with it when you get it?