Actually there is no need for something similar when it comes to Juventus. Their being competitive for the Serie A title next time would be good enough for the board. 
Even Xabi Alonso wouldn't be able to repeat the same exact season in my opinion. Because the thing he achieved was unique. This must be the best ever start to a new manager career. Anyways, Motta will need to make significant changes for sure. Transfers should be made carefully by focusing on the weaknesses the most. Midfield should be the most urgent place like I said before. After that we will find out how good Motta will do with a bigger team.
Juventus currently have many weaknesses, so Motta will have something to work on. If he managed to achieve results once in Bologna, this does not mean that he will be just as good at Juventus. I agree with you that it will be just as difficult for Alonso to repeat what he did, it was euphoria, now he will have to defend what he achieved. Maybe I'm wrong, but I think that he should accept the offer from Bayern or another team, it would be a logical step towards growing his career. Even Xabi Alonso wouldn't be able to repeat the same exact season in my opinion. Because the thing he achieved was unique. This must be the best ever start to a new manager career. Anyways, Motta will need to make significant changes for sure. Transfers should be made carefully by focusing on the weaknesses the most. Midfield should be the most urgent place like I said before. After that we will find out how good Motta will do with a bigger team.