I would have to go with Grimm on this one. Robin, as a character alone may be fine. But, when paired with Batman, it waters down his entire 'loner' concept. I mean, what is it with "loners" in comics these days? Wolverine and Batman surround themselves with fucking armies. They simple aren't loners.
Nighwing is great because he is his own, legitimate identity. As a partner (because he's way too experienced and way too old to be a "sidekick") he would be more useful, and functional, to Batman than any "Robin".
Robin is used, mainly, because of copyright reasons. And, come on, that's obvious...
