I like juventiknows' end of season report on him:
Often overlooked because of a) the nature of his position and role demanded by Conte, and b) his overall selflessness, Marchisio is simply an irreplaceable piece of Juventus’ biggest asset, its midfield. Under Conte’s tutelage il Principino really began to shine. This season he picked up right where he left off.
An excellent dribbler with exceptional ball control and passing skills, Marchisio is at times most valuable for what he does without the ball, constantly terrorizing defenders with well-timed runs into the box, and frequently (for a central midfielder) chipping in with a big goal. So well-rounded is his skillset that with the unexpected meteoric rise of Paul Pogba, Conte was able to field Claudio as a second striker in order to maximize squad selection. The results may have been mixed, but his willingness to move around for the team, as well as his ability to at least spot-start out of position during a time of need – as he had done previously as a left winger under Gigi Delneri – only enhances his overall value to the team. None of this has gone unnoticed if reports of interest from clubs like Manchester United, Bayern Munich, and AS Monaco are to be believed.