No titles, and chokes in almost all big games that matter. His team is inconsistent.
He coaches for Fiorentina. Your "No titles" argument would hold water if he were the coach of Juve, Inter, Milan, or one of the European powers, but Fiorentina is not a European power.
But I'll tell you this. That team is a lot better ever since he came on board. And how exactly is a 4th place,6th place (with a 15 point deduction), 4th place, 4th place, and now currently in 4th place finish "inconsistent"? Along with 3 CL qualifications and a UEFA Cup semifinal that Christian Vieri happen to choke during the penalty kicks?
And also, let's not disregard his eye for young talent and reclamation projects, such as Jovetic, Vargas, Melo, Gilardino and Mutu