Now, please don't misunderstand me. I am not going to argue with the credit, and I'm happy those two men—both of whom are very talented men, whose work has certainly given me hours and hours of entertainment in my life—are recognized for their contribution to the character and I assume (or, perhaps I should say, hope) that such credits bring with them some sort of financial remuneration.
I am simply curious as to why some DC Comics heroes, for example, always have the names of their creators cited in comics they appear in, why some characters never have the names of their creators cited, and why some sometimes do and sometimes don't. There's probably a degree of legal reasons (There certainly is for the current way the credits for Superman's creators appear in Superman comics now, as not only are Jerry Siegel and Joe Shuster credited, but there's also a "By Special Arrangement with the Jerry Seigel Family" following it these days).
Nightwing seems like a particularly murky character for anyone to be assigned credit for creating, though.
a 1963 issue of Superman; it's the name that a disguised Superman takes on while fighting crime in The Bottle City of Kandor, where he has no superpowers, but operates as a sort of Kyrptonian version of Batman (with Jimmy Olsen in the sidekick role as Flamebird). That version of Nightwing was returned to repeatedly in the Silver Age (as in the story under the above cover).
That comic was written by Marv Wolfman and drawn by George Perez, so they get the creation credit. But they didn't create the character or the codename, merely assigned the latter to the former, and Perez created a new costume for him, although that's been changed repeatedly over the years, and, obviously, bears no real resemblance to what Nightwing is currently wearing (I'm not sure who designed his New 52 costume, but whether it was Jim Lee, who was originally credited as redesigning the whole universe, or one of the many other artists who helped him, it's worth noting that it is essentially a refinement of his previous costume, which was itself a refinement of the costume before that, and so on back to Perez's original, I suppose).
It seems then that more accurate credits would be something along these lines:
Dick Grayson created by Bob Kane, Jerry Robinson and Bill FingerThis particular character seems like one of the trickier and murkier when it comes to assigning aspects of creation, as there's over 40 years difference between the introduction of the character "Dick Grayson" and the introduction of his Nightwing identity and costume.
Nightwing created by Edmond Hamilton and Curt Swan
Dick Grayson-as-Nightwing created by Marv Wolfman and George Perez
Nightwing's current costume designed by Jim Lee or Whoever
But Nightwing is hardly alone and having a knotty creation story. For example, how to deal with all of those Golden Age superheroes re-created as new versions in The Silver Age under Julius Schwartz's direction? You know, The Flash, The Green Lantern, The Atom, Hawkman?
Gardner Fox and Harry Lampert created a super-fast character named The Flash who wore a lightning bolt symbol over a red shirt in 1940, but Robert Kanighter, John Broome and Carmine Infantino created a whole new character with a different costume, keeping just the name, powers and the lightning bolt and red top.
Or, more dramatically, Martin Nodell and Bill Finger created their Green Lantern, a character who had the power to manipulate green energy channeled through magic ring he charged with a magic lantern the same year the original Flash debuted. But in the '60s, John Broome and Gil Kane gave a new character that name and some of the same powers, but with a vastly different back-story. And man, what about a character like Green Lantern Kyle Rayner, another new character with the codename of the original, but who spins out of the elaborate back-story that spun out of the second Lantern...?
I guess it just goes to show how collaborative these sorts of shared-universe, corporate super-comics can be.
I'm all for giving credit where credit's due, and money to creators whose creations are making money (Either because doing so is a contractual obligation or simply because there's so much money to throw around it wouldn't kill a movie studio to give the guys who forge their golden geese a coupla extra bucks here and there).
I'm just glad I'm not the guy who has to determine who created how much of what, and how to assign the credit.