Well, it might show Greg as an adult still dealing with some of the same insecurities but in a more grown - up context. Maybe he's now a dad and struggling to connect with his own kids like his parents did with him.
Rowley Jefferson would probably still be an important character. He and Greg have a long - standing friendship, and it would be interesting to see how it has evolved over 25 years. Greg's family members like his parents and brother Rodrick would also be likely main characters. They have always been part of Greg's story, and their relationships with Greg would continue to be a significant aspect of the plot, especially as they all get older and their roles in each other's lives change.
It's not historical fiction. The book mainly presents the typical life and problems of a current-day youngster, rather than having any historical context or elements.