I think one of the biggest differences in attack between Allegri and Pirlo/Sarri is just that Allegri wants a lot of bodies in the box. Sandro’s goal is a good example but it used to be like that with Khedira and Matuidi aswel, where Pirlo/Sarri always wanted to have a final pass. We ended up around the box without the capabilities of giving that pass, making things unnecessary difficult. While in defense, our line is lower and one or two midfielders stay behind to close the gaps.
All just plain and simple actually, no rocket science what the other coaches tried to create.