You're right, Tevez isn't a leader. Although, If you read the post above carefully, you'll notice that I never called Tevez a leader, only a huge loss, which like you mentioned is hard to replace. And given the loss of our pillars, we NOW need to replace them with a leader in the final third. Mandzukic is not that guy. The term embodies so much that goes beyond just abilities on the field. It's going to be a blend of vision, experience, temperament and ability to guide among other things.
I don't know enough about Mandzukic outside of watching him play, to know if he's "a leader"... Play style, he's a very tenacious, hardworking, tough player... He's not a great creator, even if he gets his share of assists, but he does have a great nose for goal, and works exceptionally hard both on and off the ball.
I expect Pogba, Marchisio and Khedira to be experienced leaders in the middle of the pitch. I wouldn't call any of the AMs we're linked with all that great in terms of being a lead in the final third. Draxler and Gotze. They're children. Zaza I expect to be a very good influence in the team, even if he's just a bench player. His confidence, his fiery passion for the game, his grinta, they are all things that suit Juventus well, and will help in the dressing room certainly. Our attack is young but I like the balance of skilled flair and fancy in Dybala, a mix of skill and raw athleticism in Coman, a good at almost everything type in Morata (even if he isn't exceptional in any single aspect, the combination makes him have world class potential), and two tough as nails, hard working, aggressive players in Zaza and Mandzukic. That's a great balance. All we lack is a CAM, and I really don't see it being a problem regardless of whether we sign a top CAM or just a good one.