Allegri, when at Milan, got Milan to finish exactly where they should have each season given the players at his disposal.
It may not have been pretty, it may have been embarrassing (when they were way down the league before recovering to sneak third) and it may have needed considerable help from referees at times (but he'll get that again at Juve anyway), but he achieved par results with them each season.
Look also at his CL record, where you would say he also performed to par - only tending to lose to teams clearly stronger than Milan (and even then they put in some very good performances against Barca).
The only exception was when they lost to Spurs, and I don't think you could call that a surprise result; the teams were pretty evenly matched at the time as I recall.