Batman: Eternal features the return of a noteworthy figure from the comics.
In the end of the second issue, it's revealed spoilers:end of spoilers
that Carmine Falcone is back in Gotham City. In the old DCU he had been in two of the most noteworthy Batman stories ever, Year One and the Long Halloween. And then he was killed off. He was also a figure in the films, played by Tom Wilkinson. In the new 52 DC, they're able to reveal that he never died, that he was chased out of Gotham City by the arrival of the rogues. Now that they're not beholden to prior continuity, DC is able to tell a new type of story that doesn't fit as well with any other character, showing someone who existed before Batman, and before the batvillains, making an effort to take the city back.
Let's say Marvel decides to reboot the Marvel U in a similar manner, so that the main book features a Peter Parker who has been Spider-Man for a few years, but isn't as beholden to specific elements of continuity. What do they gain by this? What type of stories can they tell that would be tougher to do now?
I'll note that I'm not in favor of rebooting the Marvel U, but I think it's interesting to consider the advantages of the other side.