Allegri's return to Milan would really be a great sigh of relief for the club because the coaching aspect is one area that I feel Milan has been struggling with since the departure of Carlo Ancelotti, there has been different people that have stepped into that position but none has come close to achieving something worthwhile but I believe with a competent coach like Allegri leading Milan, then it's obvious that Milan would be getting back to those days when they will once again contend for the Scudetto and the UCL.
Yes, with Allegri's funds, there may be a difference in appearance and also the strategy used. Like after Tijjani Reijnders left for Man City, Allegri also did not intend to replace his position directly. Because he wanted a slightly different midfield tactic. He will optimize midfielders who are like Modric's character.