Marchisio relentlessly passed the ball forward. Loca passes back or sideways most of the time.
A fairer parallel would be that Loca do pass it forward but he does so from much further back on the pitch. I also think Marchisio were better at set ups while Loca is more limited both technically and in vision. In Loca's defense he has improved substantially the past year. He is also quicker in his distribution now compared to a year or two ago, but behind Marchisio.
In hindsight, I was a bit frustrated with Marchisio back then because I compared him to his predecessor, Pirlo. Marchisio was a tactical B2B who's role was to balance and make runs to open spaces for others, who later was forced to DM because his knees couldn't do it anymore.
Pirlo receiving the ball was a sign for Licht, Vidal and others to make runs. Doesn't matter where or how, Pirlo could technically still see and make that pass or set up. When Marchisio took over his teammates knew his limitations, so the runs became fewer. For many years now we've been extremely static because players know we can technically not make those set ups or for that matter even spot them. Watch replays on Nico's games since he came back. He has made tons of really good runs behind defense but we don't spot them (albeit a backup GK anomaly). Douglas has spotted them on a few occassions but his split vision is too poor so he has noted them too late or he has been technically limited.
All based on my gut feelings, nothing to support all-of-the-above. I loved Marchisio, he was not a world beater but he worked hard and smart, and he was lo stilo Juve both on and off the pitch. I am not considering his hansum face but his well and civilized manner. A better regista than Loca but not a game changer either.