While Allegri's Milan defeated Inter in Sunday's derby, Cassano remained unimpressed.
He told Il Corriere dello Sport: "In Italy, we continue to follow Allegri—who deserved to win the derby—our philosophy is to defend well and hope something happens up front: but that's been out of date for years now.
Cassano went onto discuss other coaches, including Simone Inzaghi, now of Al Hilal.
He said, "Simone Inzaghi's four years at Inter were a failure: they were the strongest team and only won one Scudetto.
"My top three coaches? Guardiola, Bielsa, and De Zerbi, who, even if they didn't win, still play beautiful football. In Italy, who has won with a modern style of football? Spalletti was wonderful.
"Conte and Mancini also had a wonderful European Championship. The best national team was under Prandelli in 2012, but in the final, the strongest Spain in history faced them."