Not having Biglia is a big loss for Lazio.
There is every chance those midfielders will get caught too high up the pitch and give Juve counter-attacking chances. And if they do hold their shape, Parolo not being able to break forward is still a big loss for Lazio.
I think 3-5-2 is the right call from Allegri for this one. Not so much because of the risks on the flanks, but rather the danger Lazio would pose on the break if Pirlo was the only midfielder deep and there were just two centre-halves behind him.
I wonder if there is any chance of Lazio adjusting slightly to match Juve's shape? Could easily be done with Radu playing a little narrow and Lulic and Basta as the wing-backs.
Juve have to be very aware of the movement of Candreva and Anderson. They play with a lot of freedom and frequently both end up in a similar area of the pitch, which would be very dangerous if Juve aren't very quick in getting cover there.
You have to think Juve's midfield will control that area of the pitch, so the concern for Juve really has to be the pace of Candreva and Anderson.