Marchisio discussion is unrelated to Pastore, I barely addressed Pastore because I dont think we are getting him (though it would be practical especially because he wouldnt be non EU). Said wouldnt trade Claudio, but his flaws, or his mainly just about average hardworking overall performances (has spikes to good performances occasionally, like right now), speaks contrary to the notion of him being a special player or more delusiionally a world class one.
Pastore is no show pony (he's style is bit more practical), and he IS better then Marchisio, the sooner you come terms to that, the better. He is having a great season. And only reason he can compared to legendary players is in talent, or that he would resemble their start in his career, legendary players were young talents once, and it was obvious to see they would become real special type of player with few more years in their career. There are several other young players in this level, but Pastore is one of them, future top ranking player.