Passion is the most overused word in football, I hear it all the time from English fans in respect to players and managers. Different people react in different ways. Does Buffon walking off smiling when he greets opposition players make him less of a player? What about Del Piero when he just walks off after a loss, he doesn't show any passion?
But Del Piero is a genius footballer. His passion comes from him using his skill effectively and scoring goals. Marchisio isn't some sort of wonderkid, he's a water carrier. If he wants to set himself apart from his competition for his role, he had better show us something of value, because IMO he hasn't yet. He's a limited player who needs to rely on determination to get the job done.
What I saw a lot of in our players after games this season was resignation, that was all of them not just ones we want to pick on. When the loser mentality is lifted we'll see better from all, but you take the rough with the smooth, can't just focus on extremes.
But that's hopeful optimism. Marchisio has always been the same player -- a guy who does his job and works relatively hard, but doesn't take it to the next level. He can't take it to the next level in terms of ability because he doesn't have it, but he can up his energy and determination. There's no evidence to support what you're saying because we haven't seen it in the past, even when we were relatively good under Ranieri. It's similar to saying I'm going to fulfill my potential in multivariable calculus just because I had a good GPA the semester I took the course.
To answer your other question he is most dangerous making late runs into the box, but he's rarely there because he is off playing a restrictive left midfield role, or playing the water carrier role in the centre. The answer I don't have is where the guy can actually play in a modern system to make the most of his abilities. In a 5 man midfield as the offensive LCM or point in the 4-3-3? He doesn't have a shot like Scholes or Gerrard or the passing to play deeper but does link well with forwards. Not that this is the real challenge, the challenge is to create a strong Juventus before a strong Marchisio, the rest normally follows, but he either fits in or he doesn't.
He just doesn't have any real useful qualities besides being a water-carrier. Period. You know this as a fact considering what you just wrote. Without quality players around him, we won't get the best out of Marchisio, which makes him dispensable unlike some destroyer or holding midfielder who does his job no matter what. That's why Marchisio needs to take himself to another level of grit and determination.
I see. I know very little about tactics and formations but to me, it seemed that the reason why Marchisio was kind of lost in the middle of the pitch in a fair number of our games was mostly the chaotic and disorganized way of our play. He was much better under Ranieri and in the games when the team was naturally organized due to be super motivated like the games against Inter. I agree that he is still nowhere near what we expected him to be but I can safely say that these "Juventuz next captain" or "the homegrown talent" stuff are not why many fans are still reluctant to give up on him. It's got mostly to do with the fact that he has already shown signs of becoming a very good player for us if coached and trained under the right guidance.
I think he's only going to be solid if he plays in a good team, not someone to
make us a good team. And that's why he's dispensable. But I for one want to keep him because he's suited for the 4-3-3 next to two competent players and he is a Juventino.