Yes Juventus has major issue. Their defense is strong but their attack is weak. Tie with Cagliari was frustrating. Manager Motta midfield strategy did not help their offense. But their defense is solid because they have four defenders.
You can say their good defense is because of their players and coach or don't attribute it to the coach, but I believe that a coach and his tactic play important role at any team. Thiago Motta is doing well with his tactic and player choices in Juventus, to work hard with players for the solid defense. It's unfair to say Juventus good record in defense has no contribution from the coach.
However their forwards especially Dusan played poorly. They missed many chances and fell unnecessarily. Seeing them waste opportunities is painful. Dusan might not be good enough anymore. Juventus needs to find better attackers.
Dusan Vlahovic is no longer young and he possibly passed through his best time to have break out for his career. In other words Dusan hits his best and will no longer be a better striker in future. With time he will be older and get more injuries and golden time in a player career does not last long. Dusan is a striker or sometimes as a central forward but Juventus need more good attacking players at their two swings to support Dusan with good key passes and assists.