Vialli's two former clubs meet in the Champions League on Tuesday just days after the Old Lady tried and failed to breakdown Lazio.
"Juventus' issues in attack revolve around the fact that their forwards are all on the same level," he told Tuttosport.
"Nobody has illustrated that they are world class and that is why boss Antonio Conte rotates them in the way he does.
"The side can benefit from that ploy as a result, but the individual players certainly won't.
"It is hard to choose which pairing to go with, because there is not one which you can say is the strongest."