Cassano played in Euro 2004 and 2008, but has been consistently frozen out under Marcello Lippi's reign.
"I believe that the Nazionale should have players of talent, not so much in qualification, as Italy always go through," said the former Inter Coach on Sky Italia television.
"In a World Cup class really counts, as a game can be decided by a player who might have other limitations.
"I think quality and class are indispensable in a major tournament. I am not the Italy boss and so it's not my issue, but as a fan - without offending anyone - I am disappointed Cassano is not there."