I think he is failed on both from the making of the film and from in the film his family and pride fail him.
In the film he isn't really given any potential to show who is is or what he could be. As for his position in the pride its stated that Kovu is the chosen of Scar so Nuka is practically just ignored and cast out. The one thing he does show is his willingness to fit in and get attention from his mother which he doesn't get.
[quote="matkiethelioness"]Nuka is one of my favourite characters in the whole TLK universe. I find his death sadder than Mufasa's(COME AT ME). He just wanted his mother's love and respect...
[/quote]
Although his death is sadder I would agree with that, but in a different way. It was nowhere near as powerful or moving because they hadn't built him up and got you feeling for him in the first place.