Lampard is most definitely a valuable commodity and would slot in very well in Juventus.
The thing is, the list of world class football clubs with either a gaping hole in midfield or a desire to retool is pretty limited. To bring in a player of Lampard's stature and quality is to assure a starting 11 place for them come hell or high water, much like Trezeguet and Buffon here and to a lesser extent, Nedved and Camoranesi.
Juventus is the only one that really, really needs a midfield upgrade, since Nedved is more than likely retiring (with his actual swansong being Euro 2008), Zanetti (while doing awesome) isn't getting any younger, and the idea of playing a two-destroyer midfield in CL is concerning at best.
With the added burden of CL, I see no reason why Van der Vaart, Lampard, Marchisio and Giovinco would be unrealistic... seeing as Nedved, Olivera and Almiron are definitely out, and likely Tiago as well.