I see Robin in the Tim Drake style ninja outfit, only with red and green instead of all black, even though I'd prefer Dick Grayson to appear first. I definitely don't think it's a good idea to have the Joker kill his parents though. That was a big problem with the first movie. Not everything needs to be connected. I don't like the idea of Joker "creating" Two-Face either, but that's another story.
I recently read the actual first appearance of Robin back in Detective Comics in the 40's and even they got it right despite the mild camp that was prevalent anyway. Robin is a direct reflection of Batman: He's lost and has nobody, and it's Bruce's opportunity to take in and care for somebody who is in the exact position that he was in all those years ago. He has the chance to curb the boy's anger and resentment and channel it into something good. That little oath by candlelight is awesome and would make for a great scene between Bale and whomever they cast as Dick Grayson, so long as the cheese and triteness of it is filtered out, leaving only the core emotion and impact of something like that.
This, of course, is MANY movies into the series now. Batman can't possibly father or mentor anybody for at least three more movies. He's just learning himself. He's honing his skills as a detective and a crimefighter and needs the time alone to cement himself as THE pro. Robin will come along once Batman has gotten so good at what he does that his psychosis and habit is actually pulling him further and further into the dark side. He wants to be Batman more and Bruce Wayne less, he's becoming a workaholic about it, and it's taking a toll on his health-both physical and mental. That would be the perfect time to have Robin because that's what Robin's primary role is: to hold Batman back from going so far off the deep end that there's no sign of a shore anymore. Robin is the human side of Batman-the human side that he's slowly losing as his obsession with doing what he does grows bigger and bigger over time.
I don't think that Christian Bale and Christopher Nolan see all that in Robin. They kind of see it as a way to lighten Batman up and make him more kid-friendly, and while he DOES do that, it's become so much more. It's awesome storytelling if done correctly, which I'm sure David Goyer would if he wanted to continue writing for the series. Robin is underestimated, sadly, and not a lot of people really get how vital he is in keeping Batman more human than not.
Like I said, this is A LONG TIME after the events of Batman Begins. Once that's established, there's no way they can go wrong if they play it the way I've mapped out. That's a non-camp, important, interesting, and worthwhile Robin.