I agree that Bonucci's defensive ability, alongside the often nebulous concept of leadership, are somewhat overplayed on here.
That said, everyone agrees his passing ability and, perhaps more importantly, his vision are all but unrivalled in the position. He is, in every way, a CB cut from Pep Guardiola cloth and would be a natural fit in our system and squad.
Those expecting defensive contributions beyond Otamendi and Kolarov, arguably both of whom have been unassailable this year, would perhaps be disappointed. But we didn't bring in Stones for his tackles and interceptions, but his play making which is the perfect fit for the style and system we are developing. Possession and pressure are central, which helps ease the defensive burden too.
Bottom line: we're much more likely to target defenders that are better at Pep's game than those that are better at the traditional fundamentals of the position.
I'd have imagined the club would try their hand at Laporte again before another run on Bonucci though.