There's a difference between Kreider "playing with an edge" and just taking sloppy penalties.
I'm not going to solely blame the too-many-men call on him, but he's taken a number of stick-related penalties, and a bunch in the offensive zone. If he can shore that up a bit, he'll be in really good shape.
Do you want him to be aggressive or not? If you play on the edge,you are going to use your stick and take penalties. Kreider shouldn't be concerned about winning the Lady Byng. He is 6-3 230. If he slashes the goalie trying to knock the puck out of his glove or trips the opposing player,that is part of the game.