In my opinion what he did here with agnelli is nothing short of legendary. We can all agree on that, specially taking in consideration what happened in 2006.
As of today, i think he is a juventus legend.
IMO what can really tarnish his legacy here is if he go all disrespectful towards juve saying things that are obviously forced, like the revoked scudettos being rightly revoked etc. He should man up and try to explain this situation to his new employers if the time of answers this questions come. Answering to the media that he is in there to take inter to new heights yada yada, but that he will not talk about juve on the media etc, regarding those matters.
He should really focus in strictly inter matters and look at juve as competitive rival, nothing more. Treat juve as the past, as if nothing happened.
I repeat, if he starts going all gung ho against juve, and embracing inter's calciopoli version like if he never was here, then his legendary status should be questioned.
No matter what his contribution in juve WILL be legendary, but his status as legend should be discuted from now on depending on his stance.