He might not score wonderful goals like Quagliarella, but other then that I dont see what Matri or Quags have that Zaza dont. Zaza is very physical and despite his technical qualities, he reminds me of Balo in terms of playing style..
Pogba has showed how it's done. And like Marrona said, it's better to have 15 games with a world class club then 30 in a small club. If you train with the best, you learn from the best, and we easily have 15 games for Zaza or some other youngster next season..