With the success of this last one, and the inclusion of so many characters, and the broadening of scope, when we were sitting down to figure out what would fit into the real estate of number six, we didn’t have enough space,” Diesel told THR
Apart from reuniting supporting characters from previous movies, it added star power in the form of Dwayne Johnson. A coda at the end of the movie teases the return of a character played by Eva Mendes last seen in 2 Fast 2 Furious as well as the return of Michelle Rodriguez.
“We have to pay off this story, we have to service all of these character relationships, and when we started mapping all that out it just went beyond 110 pages,” Diesel explained. “The studio said, ‘You can’t fit all that story in one damn movie!’” - The Hollywood Reporter
What that means is they are making a Fast and Furious 6 and 7. Now I know they are not the best movies to put it lightly, and I don't see them at the theater (even though getting a look at that crowd may be worth ticket price alone), and sometimes not even on pay per view. But for my money it doesn't get much better than waking up hungover on a Saturday or Sunday (sans football of course) and seeing that you have 2 hours of nonsense of ahead of you. Granted I may be nearing 35 by the time FF7 comes out, but that unfortunately probably doesn't change anything.
This also keeps Diesel relevant enough to be let in at the playboy mansion and gives Walker enough funds to keep cultivating rice of the coast Indonesia.