They need to make a TV show about the Marauders. Not movies. A TV SHOW. Start season 1 in their sixth and seventh years, capture what it was like being at Hogwarts, struggling to cope with their complete loss of innocence, being at school with Slytherins they know hurt people they care about.
Have flashbacks throughout the show of innocent fun moments when they were younger.
Dig deep into Slughorn's affection for Lily, McGonagall's relationship with the Marauders.
Actually portray a graduation scene this time, capture what it was like balancing school and the raging war outside of it. Season 2 covers life outside of Hogwarts, Voldemort's attempt to recruit them.
Dorcas' murder, Mary's death, Marlene and her family's slaughter, Gideon and Fabian's death, the Longbottoms' torture and Moody losing his eye.
Have it end with the scenes cutting between Sirius confronting Peter and the Potters' deaths. Show Sirius in chains, cut scene to the Potters on the ground, dead, have a moment where Slughorn comes down the stairs and Lily's fish is gone.
End it with Hagrid picking up Harry, the people around the world toast to him, the dawn rises behind Hagrid and Harry to symbolize a different future ahead.