Of course it was a smart move. Maresca is not half the player of Vieira and while Appiah IMO is a decent player, he certainly is worth giving up for Vieira. Although I do think Appiah will improve over time, and when Vieira and Emerson move on you might regret giving up on Appiah because he does have a lot of potential. Perhaps in Istanbul Appiah will improve greatly, and thus far I think he has played very well next to the likes of Alex and Anelka.
As for Vieira, his form thus far this season has been impeccable, and he is probably the most complete middy in the world today. Andy told me Vieira has not set a foot wrong on the pitch yet for the Bianconeri, and from what I have seen that assessment is certainly correct. I am also impressed with the passion Vieira has shown on the pitch, and it's probably a joy for him to play for such a prestigious club and challenge for the prestigious Champions League title. With the way Juventus has played thus far, I would say the CL title is a great possibility.