From a Micah Parsons production standpoint, I could care less if he practices another day in his career. The guy is one of those freaks of nature that could not practice for weeks step on a football field and simply dominate.
The issue I worry about is you lose that attitude in practice without a guy like that there. I'm sure many have heard the Aikman interview where he talked about begging Michael Irvin to practice when he was hurt just because the intensity level is so much different without him. Parsons is sort of the defensive version of a modern day Irvin.