He made the difference on a number of occasions, providing crucial goals and assists in big games. That depended on how the coach used him. Also he was one of the best passers around when he played as a regista. Maybe not as good as Pjanic, but close (to me he made forward and less horizontal passes than Mira). In Europe, there were not many better passing CMs at the time (Pirlo, Xavi, Modric?). His ball control was excellent and he rarely gave away the ball, and did well when pressed. Defensively he was also strong - interceptions, tackles, positioning.
Maybe you don't have a grudge against him, but against fanboys. I remember the arguments that go back to the Delneri days, when you were DelPiero84

. In those days you could've been justified for calling him a mere squad player, but if you say the same for the period 2011-2016 you're just being stubborn