People seem to think that keeping a system intact is more important than signing world class players.
Let me ask those this: what players win us games? Is it the system? Or is it certain players?
Exactly, it's certain players. Del Piero, Amauri, Camoranesi, and once Nedved. This is why a great manager such as Brian Clough would sign players before caring about a system.
But this doesn't make your arguments less meaningful. What makes your arguments somewhat void is that players such as Sissoko, Camoranesi and Zanetti have played under a diamond midfield before, so all they have to do is regulate themselves a bit more at first and become familiar with the new system for it to work. All these players have played such a system so some are claiming nonsensically that our players would be stifled if we used such a system. Nonsense. The system is what you make of it, and with strong players such as Sissoko, they can fill any role as long as you tell them what to do.
This is the crux of the situation. If we don't want to sign the best players around, then we really are indeed falling behind our own frailties.
I generally like your quality players argument - clearly I want the best players possible on my team. However, if one's not careful, then that can easily become an overly simplistic and largely subjective position.
It's not as simple as saying 'because some players have played different roles in the past, in different circumstances, than it'll work great again'. Even if those players you mentioned above could adjust well to the diamond midfield, my primary concern for the system changes would be the subsequent decrease in support for our unspectacular defense! Until the back line is further solidified, the 4-4-2 provides solid balance - I think said balance is evident from Juventus' current record.
I'm not worried about Sissoko, Camo, or Zanetti. I'm worried about Moli, Grygera, and Mellberg. How much time does Marchisio get? How well does De Ceglie play the left side of a diamond midfield (seeing as Nedved won't be around soon, and we have no other legitimate left footed mid), do we want Marco Marchionni to EVER play the right side of a diamond formation (Haven't seen it, but I'm thinking NO), etc., etc.
If you add Diego, and in the process make a bunch of players less effective (or obsolete), the results won't be as beneficial as anticipated - that's all. If it was summer, and there was an opportunity to make additional player changes, and time to really drill tactical adjustments etc., then a move for Diego would make considerable sense for me (as long as we had enough cash left to fill at least one more of our needs, and Ranieri was dedicated to a change in formation). In fact, if we sign Diego this summer, I'll probably celebrate like it's my fucking birthday!
But you can't say 'it's all about the players' when it's midseason, when we're chasing the Scudetto and getting ready for the knock out stages of the Champions league. Team management is clearly a HUGE variable; continuity, unity, and general player comfortability are key factors for the locker room; chemistry is hugely important for a team with Championship aspirations. Introducing one player who will significantly impact 5+ other players could severely harm Juventus' chemistry for the short term. We need seamless transitions at the moment - the schedule is about to get very tense.
BTW,what's your problem with Zhirkov? You think he's simply overrated? Everything I've ever seen and read has demonstrated to me that he's an excellent player (who could play in a couple of positions we need help at).
I'm not arguing against the quality of Diego, nor am I saying that I wouldn't love to see him at Juventus. I just think that at this point in time, for this season, Zhirkov would likely be more useful. He's only 25 and I think he's CL eligible as well, isn't he? We've gotta find someone to play that left side now.
Personally, I have a strong feeling that the day Diego plays for Juventus under Ranieri will be the day that it becomes mandatory for houses in flood prone areas of New Orleans to be constructed from gingerbread and gumdrops.
I honestly think that there is no way in hell he comes to Turin in January. It's possible that he could move in the summer, which would be awesome. Either way, we've got a LM slot that needs to be filled NOW, and multiple slots on defense that need to get filled ASAP - those moves should be the priority.