Is Holden just a spoiled rich boy who doesn't appreciate how well off he is or does the novel raise concerns and issues that have a universal concern?
I would agree that both aspects of this statement are true. Holden has moved through several prestigious schools without commitment or sincerity towards himself or others. He seems unappreciative of the opportunities he has as he feels they are as 'phony' as the individuals who operate within them.
It is more of a universal concern that not even Holden can resist being 'phony' - asking Stradlater not to tell Jane has has been thrown out of Pencey, for example. Holden minutely observes those around them to reveal their 'phoniness' which in turn highlights his own. The peace he strives for in terms of a genuine relationship are sadly beyond his grasp and the novel implies this may be so for us all.
Is there a reason that this has to be either/or? Can't the answer just be "yes?'
I think that Holden is a spoiled kid who does not appreciate the opportunities that he has. However, that does not mean that his concerns are not real.
I think that many teens feel the way Holden does, even if they are not spoiled rich kids. Teens often feel that other people are phony and they often feel like everyone is in some way out to get them like Holden does.
So I think Holden is spoiled, but I also think that a lot of teens feel angry and alienated because they do not like the way that society makes them feel.