Pirlo is a huge defensive liability, whilst apart from freekicks, Marchisio offers significantly more and allows us to play far better in the midfield, even if its Sturaro and not the mighty Pogba.
You go ahead and play Pirlo. Meaning Marchisio and Vidal will play a lower quality game due to obvious restrictions. Meaning Madrids midfield will cope with ours, meaning they should have not much problem reaching the wingers and make plenty of offensive plays.
You are missing the point. Its not about Madrid pressing us, its about our ability to press Madrid. We absolutely need to win the central midfield and cut of the fast supply to the wingers. Madrid will have great difficulties playing against a Marchisio, Sturaro, Vidal, Pereyra midfield, and thanks to using Marchisio as cdm, we can commit far more players running deeper into counter attacks, wich you simply cannot do when you have Pirlo.
And we've allready seen Marchisio can launch plays just as good with his balls over the defence.
Its not about Pirlo versus sturaro. Its about Marchisio versus Pirlo and the whole playstyle shift that comes with it.