Giovinco would likely be used for Coppa and some league games against weak Serie A teams that Diego would not be needed for. He could also be used as support striker in place of Del Piero with Trezeguet, Palladino or Iaquinta. Diego would get CL and most Serie A games.
Seems to work out fine. Top teams have top quality depth.
I'd like to keep Tiago and dump Almiron as I think Tiago has not only shown more, but is more likely to continue to grow and improve with the team... but like the Marchisio v. Zapata scenario in another thread... you have to make the sacrifice in Tiago to get the superstar in Diego.