Suh was guaranteed to get cut this year from the moment he signed that ridiculous contract. Anything short of carrying the team on his back to a Super Bowl victory (and when was the last time a defensive player did that) meant he wasn't going to be with the team for the 2018 season.
No team is going to pay a defensive lineman 14% of their cap. Miami was either stupid (not entirely out of the question) to sign him to that contract, or they knew exactly when they were cutting him.
Neither his on-field, or off-field, behavior have been bad enough to excuse the cutting, so you are going to see some waffling about exactly why he was cut, and the locker room cancer excuse/ just looking for guys who want to play football excuse are going to get tossed out there.
It's simple economics, his contract was too big to keep for a team that isn't a perennial contender.
He isn't the same dirty player from his first two seasons. He isn't a locker room cancer. He is just a top 5 talent toward the tail end of his career. He likely has 3-4 good years left, and I hope he spends 2-3 of those with us.