thing is though, if you go take a look at SeanGares review he did of their demo's, he said that its actually not the mid-late round calls that are suffering like everyone thought it would be, due to the language barrier. Its the set strats. When they play Mirage their set pieces are just executed poorly. Mid takes are dont with no trade ability so they are consistently down a player.
Stewie could have been an amazing edition to the SK Lineup, but they dont keep him loose enough. The most loose we saw him was the solo awp B holds on Inferno where they still lost A site numerous times.
Think of the C9 Major game against FaZe, they left Stewie solo with an awp on B, he consistently killed 2-3 people, even saving the major for them like 4-5 times. Because C9 was loose enough to just let him get on with it and focus on their own game.