Many argue that the new franchise does not need a Robin. That it is too dark and that the character wouldnt fit and that the public would dislike him and seem to. I personally would love to see a Robin within the movies. The character premiered a year after Batman, after all, so much of Batmans legacy is with Robin than he was alone. I think, somehow, it can work. The moment Batman gave that young boy a batarang to prove to his friends that Batman actually existed in Begins, I immediately was reminded of the current Robin, Tim Drake, who had a long standing obsession/fandom of Batman (and the former Robins) and of the animated series incarnation, who had picked up a batarang from a crime scene. That moment alone could set up a possibility for a Robin in future installments, though highly unlikely. I feel this character needs to be handled delicately. The two movies featuring Robin in the nineties were an unfortunate mistake and were not approached correctly. In my opinion, they cast the character far too old and was horribly written (not to say the rest of the characters were written well either, the movies were horrible examples of what not to do, ever.). I think within the Begins mythos that there are one needs to approach the Robin issue more realistic. Granted, a time skip is needed of course, since the first two movies take place in Batman's relative, well, beginnings.
When the time is appropriate, one could go the classic Richard Dick Grayson loosing his parents due to the mob (or whoever). Whether or not he jumps right into the Robin role, I am quite hesitant to say, but I think it would be interesting dynamic to have the brooding playboy find a literal mini-me, NOT the "gee whiz" ball of energy and hotpants we peg him as. I think this series Robin should be a lot like Bruce, not angry and cocky, but kinda withdrawn.
But, thats just me. I have tons of ideas, not saying they're any good or obviously useful, but it needs to be thought out. This is where they need to write the story well, since the original sudden adoption of Dick in the comics eventually brought accusations of homosexuality, (hence the creation of Batwoman and the first Batgirl) and the idea that Bruce would, within short notice, take care of the boy out of the blue, is something that can be seen as somewhat perverse and ridiculous and needs to be treated just as careful as the character itself. Its hard to imagine anyone let an adolescent or teenager fight unless they do so without any disregard to what their elders think or tell them to do.
Now, to move around this, they could do a few things, such as tinkering with the mythos and perhaps merging various aspects of the multiple Robins as seen in the animated series, where they had blended the characters of Jason Todd and the current DC Robin, Tim Drake, together underneath the identity of the latter and omitting the former completely. Im not saying to change Dicks character all the way, but perhaps alter how he ends up under Bruces care, or as Robin. Either or, or both. Heck, they dont even have to have Dick be adopted by Bruce given the minor realistic tweaks occurring in the movies. Pretty sure Joker has a totally new backstory (or lack thereof) right? In past incarnations, Bruce Wayne has always been present at the Flying Graysons deadly circus performance (pretty sure he was), and I think perhaps by creating a scenario where he isnt present could be an interesting way to go. Perhaps it is the classic scenario; a double murder/accident, but is more something that is all over the news due to speculation of mob involved sabotage and assassination. From there, the newly orphaned Dick could appear into Bruces life in some other way. I had the idea that Dr. Leslie Thompkins, being the benevolent person that she is, could perhaps have ended up fostering Dick by coincidence since the boy is under eighteen. As a side note, within the new movie mythos, I would imagine the best age frame for Robin would be anywhere between thirteen to fifteen, but nothing older than that as it seems fitting and is closer to when most of the Robins actually did take up the mantle....more or less an estimate, it's probably younger *shudder*. By being under the care of Leslie, at her office, etc, he would eventually meet Bruce Wayne through association, perhaps a day visit or demi-Batman related visit for discreet medical treatment. There Bruce could see himself in the distant Dick. Leslie, noticing the similarities as well, would push Bruce to attempt to talk to Dick and talk about his own experience in loosing parents, and the relationship between the two could start from there maybe?
It could then be something as simple as Dick figuring out that Bruce Wayne is Batman and like I like American_Idiot's idea, offering to be some sort of mole or have Dick be some sort of wiz-kid like Tim and after figuring out who Batman is, becomes some sort of anonymous informant for Batman without Batman ever figuring out who he is, and Robin would, as American_idiot suggested, be just a code name he would sign his notes or emails.
Maybe even make him a young Batman fan who attempts to thwart small crime to draw the presses (and Batman's attention) since I would assume any orphaned child would want attention. (hell, he doesn't even have to be an orphan if he's a wannabee) His antics could possibly cause more (major) trouble than the crime he attempts to foil. I'm imagining causing a large traffic accident in particular, being caught dangling from a grapling hook swaying in traffic, nearly getting hit by a car, both somewhat funny, but serious in a " Oh don't go and do that" kinda way. They make grapling from building to building look far to easy, I'd love to see them poke fun at that. Batman was not perfect in Begins, so a boy should be even more inept, despite his unusual acrobatic skills.... His antics ultimately then DOES catch Batmans attention, who corners the scrappy boy after a slew of botched attempts to be a hero. It could be edgier and poke fun at the ridiculous idea that a teenager could fight crime the way Robin is portrayed to do. He doesn't even have to become Batman's partner, I mean ideally yes, but it doesn't have to be.
Really, having any figure symbolic of Robin would be adequate. Hell, put a girl named Carrie bugging Batman to let her help and getting flat out rejected, and that would be enough, not ideal, but enough, and she's not even canon!