Ok, beyond the fact that stirring up conversation seems to be Bob's entire goal let's see a couple of the arguments made.
1. Robin wouldn't work in the Nolanverse: Why not? I would be willing to admit that not the campiest Robin, nor the 10 year old version (Though there are shaolin fighters who start younger than that). But someone or something to bring Bats out of the brink could be a good thing. Nolan could easily keep the dark version of batman, and introduce a very tragic Robin without sacrificing seriousness or much realism; supposing that he played Batman as the father figure, while Bruce was sort of incapable of filling the hole in Robin's life with money, or whatever.
2. Batman is always dark and gritty: No, no he's not. This is one thing I agree wholeheartedly with Grant Morrison on, Batman has gone through many phases in his life, and they're all relevant. The dark Batman from the beginning and 80s are just as much apart of the Batman mythos as the Adam West batman style from the TV show, and comics from the 50s and 60s. Even in the comics there has always been a separation. Batman's main title has usually been about any Batman story someone wants to tell; he can team up with superman, go into space, or hang out in Gotham. Detective comics has been the gritty noir crime stories traditionally.
3. Batman is a loner: Since we're talking about the Nolan movies I'll stick to that version. Bruce/Batman was constantly trying to let people into his life. Especially initially he's much more trusting than he usually is in the comics. He uses Lucius Fox, Rachel, and Alfred. And in Regards to Rachel he works on letting her into both aspects of his life, and he suffers for it. It might be an interesting dynamic to have Robin involved with Batman only, and then eventually he's let into Bruce's life once he's able to defend himself or something like that.
For the record, I do like this thread, and there are plenty of reasons to keep Robin out of the movies, not the least of which: It's quite easy to screw up. But overall I am very for Robin being in the movies. If you want to see camp taken seriously then read the last year of the Batman and Robin title. Sure it's not Bruce under the Cowl, but it's still Batman.