Why is Nicholas at all?

Nicholas is easily the most obnoxious primary character in the novel. He acts impulsively, preens his masculinity, consistently makes stupid mistakes, values honor to a detrimental degree, and holds the Emperor in a reverence that borders on creepy. At the same time, he is undeniably good-hearted and ethical. Put more concisely, Nicholas is a model for immaturity, and he stands in sharp contrast to the other older, more philosophical primary male characters. I suspect that Nicholas is included as a complement to Andrew, both in their opposite backgrounds and in their wildly different personalities. Nicholas, to some extent, shows the results of nurturing and love while Andrew shows the results of discipline and instruction; Andrew is more sophisticated and competent while Nicholas is more kind and naive. However, there is still some value in Nicholas individually. First, his naive beliefs about the glory of war and the Emperor sets him up for disillusionment, allowing Tolstoy to get didactic on the horrors of war and great men. Also, by his youth and the consequences of it,  he both allows the romantic development in the novel and lodges a subtle criticism of it (that, at least in Tolstoy's time, people chose their life partners in their period of greatest immaturity). Still, characters like Nicholas are made to change, and his outburst at the end of book five indicates that he is becoming self aware and maybe even likable. Why do you think Nicholas is included among far more ideologically complex, likable characters? What do you think of him generally?