well from what i saw when he was in charge of chelsea. Ranieri has a good quality of bringing out new talents (he is the one who brought lampard, terry, rubben and chec) plus he is a very nice guy with a big heart.
but the thing i dont like about him is the fact that he rotate too much. almost no one have a steady 1st team position which means that no player will reach his full potential but everybody will get a chance.
i dont know if i want him at juve but i dont see another candidate that will do a better job than him, maybe nouvillino. plus he wont have many problems with the managment
vialli was great at chelsea, but it have been a while and i cant judge him now