The thing is, I really think we need to prove ourself in Champions League one season or two before really becoming an attractive destination (to players outside Italy)! Of course our 30th title has won us a lot of respect worldwide, but I think the reason why players like Van Persie don't think Juve would be a move up (which it definitely would be) is because we haven't been consistent enough the past years, and I think a good perfomance in the next year's Champions League (and at least a top two position on Serie A) could prove a lot of players wrong.
That's why I think Cavani would be a crucial signing. He's a world class player and he knows for sure that Juventus is an amazing club. He already knows that Serie A is a great league, and he doesn't think that Premier League and Primera Division are the only two decent leagues in the world. Sadly, I think it's going to be hard to attract the best of the best players on the market in this window because - first of all other clubs offer more money and secondly because Serie A sadly just isn't as attractive as Premier League or Primera Division for players outside Italy. We need to show everyone that Juventus can beat everyone in Champions League (just like Bayern did for Germany this season).
Cavani could really be the player to bring us back in the spotlight! He's already getting a lot of attention in Napoli because everyone thinks they are playing entertaining football, but if he joined Juve he could really complete an already amazing team and make it possible for us to win even Champions League. Furthermore, even though he's a star in the football world, he doesn't take the attention away from the rest of the team like Ibra. He really is a team player.