Marchisio is not a DM, no. He is a box-to-box CM. What I'm saying is he can play in a 2-man midfield. Of course CM partners should complement each other. You wouldn't play Makelele and Mascherano together in a 4-4-2 nor Scholes and Xavi. England had problems fitting Gerrard and Lampard together so they moved Gerrard out wide and tried all kinds of things.
Marchisio--Vidal could work if we had particularly capable and creative wingers. For Juve, I'd say 4-3-3 with Vidal--Pirlo--Marchisio is the best option.
We'll see if Vidal--Pirlo works. It may, but Vidal will then not be the attacking threat he was with Leverkusen as he'd be forced to watch Pirlo's ass.
Why have we all been fooled into believing Conte plays a 4-2-4 formation, that's just ludicrous - a team playing 4-2-4 would get slaughtered on most occasions, even if Rambo was playing CM.
He just likes his wingers to attack a bit more, but it's still a standard unimaginative 4-4-2
Bottom line is Marchisio is not a starting player, he has no real outstanding qualities - no vision, no short-passing or long-passing game, average speed, weaker than a kid, not creative, lacks ability to control the tempo, he's not and will never be a starting CM.
Fact of the matter is Marchisio is a great bench player to have.