I haven't seen any of their recent games, but I saw a few earlier in the year. Based on that, I believe that Stewart would have been a major difference maker on the SU team. He would score whenever they fed him in good post position, and was a monster rebounder.
When they started their losing streak, I felt that one reason for it was that they were unable or unwilling to keep feeding Stewart. It seemed that the wrong guys were jacking up 3s and auditioning for the NBA, instead of playing winning basketball. As I said, I haven't seen their most recent games, but it may be that Stewart doesn't look as good now because he doesn't get many touches any more.
No doubt their guards are terrible and do a very poor job of getting Stewart the ball. WSU has no front line to speak of yet when Stewart did have the ball last night he didn't do much with it. Maybe he just had a bad game. Like I said, I know he would be additive but I just don't think he'd be - to put a finer point on it - vaulting us into the top 20. I think he could use another year of seasoning but prolly not at UW with those lousy guards.