I think the biggest difference with Kuyt under Kenny, is that he is doing all his work in the attacking third of the pitch. Under Hodgson and towards the end of Rafa's regime, the team was that defensive in its approach, that Kuyt was often in the right-back position. When he received the ball he was in his own half, and with his lack of pace, he never troubled opposing full-backs. Now when he gets the ball, he is already in an attacking postion, so his lack of pace isn't so apparent. Also, Kenny's attacking philospohy has helped. Kuyt's first touch used to be backwards, which meant he would invariably end up passing back to Johnson or inside to Lucas, but now once they receive the ball, the players (Lucas another to benefit) are on the front-foot looking to attack.