Juventus still have a lot to work on their team because right now they are not on their best performance and it was even with struggling they were able to secure the third position they did on this season making them to qualify for the champions League next season, so perhaps if is a club that needs to improve next season they will never hesitate to recruit more capable players because last season may likely be nothing compared to what they will see next season, so preparing ahead of time will be actually a great beneficial to them so that before the next season they will be ready.
Yeah for now especially with their performance this season I don't think they will be a threat to other team next season because they don't have what it takes now, however is very obvious that they will find it difficult to cope on the champions League because their are so many clubs there that's doing very well more than Juventus so if they failed to invest on more players I'm afraid they may not even be able to qualify from their group stage.
Juventus with its new coach will definitely make changes to its squad, but now Juventus has to start everything from scratch because every coach needs a process to improve a team's performance, but sooner or later we don't know when Thiago Motta will build the Juventus team.
If you look at what Thiago Motta has shown with Bologna last season, Thiago Motta should also be able to do the same thing with Juventus.
The team with its new coach for next season will be different, so what happened last season cannot be any benchmark for what happens next season so I think it is unfair for us to compare or predict what happened because of last season.
Personally, I am quite optimistic about Juventus next season and now we just have to wait for Juventus management to recruit new players and the management should be able to recruit quality players according to coach Thiago Motta's wishes.