But that's the comics. Of course Robin is an essential aspect of the Batman character... in the comics. Few would argue that. But in these films - if the reviews are to be believed - Nolan has now crafted two excellent, fully-formed Batman stories, neither of which feels like it's missing something for lacking Robin.
When you go onto a third film, true enough, you need to progress the Bruce Wayne character. But I'd hardly say introducing Robin is the ONLY way to do that. The Nolan brothers are imaginative guys. There's another, equally-enduring central character yet to be adapted, who could fill a similar role of offering a foil for Bruce, while at the same time possibly being a better fit for Nolan's Batverse. Of course, I'm talking about Catwoman. Not saying they have to use Catwoman either, mind, just showing there are alternatives to Robin - it's not the ONLY option for film three.
I'm not totally unsympathetic to your plight though, Freddie. It's easy for me to talk about how the character isn't needed, when my three all-time favourite comic characters - Batman, Joker, Two-Face - are being featured in "The Dark Knight". It must be frustrating, when your favourite character isn't making the cut.