Stewie's biggest asset is bringing energy and passion to a lifeless team. Like he did to the repetitive, quiet zombies of Liquid when he joined. That's why they went on a winning streak. Their energy increased dramatically, which increases communication and overall morale. Once they started losing matches they were expected to win, the other guys went back to their old ways. Other than that, stewie is an all around player that would best serve as a support/lurker at this point. He's no awper. He's no IGL. Can he play those roles? sure...does it take away from the nuances of his game that improve a team overall? yes...autimatic is the same way. He may have wasted his prime away by being loyal to c9 for a year in a dead team. But he got even worse once he tried to IGL and awp. No longer the impactful player that he was.
Bottom line.. Stewie is the NA equivalent of NiKo being an IGL. It's a waste of time for everybody and hurts the team more than it helps.