Okay, this part is really important. The real question is, what is Kevin’s perspective or worldview that comes from his personal issues?
One possibility is the view I’ve been espousing. Everyone treats Kevin like an incompetent little kid, but Kevin feels he’s much more competent than people give him credit for. No one gives him a chance to show that he’s actually pretty smart. It's not his fault no one's ever told him how to pack a suitcase.
In this view, wishing his family would disappear isn’t his perspective per se, it’s more of a reaction he has to how people treat him. I was even thinking it might fit in the IC throughline, an Impulsive Response to his mom’s harsh treatment of him. Even look at the way the dialogue goes:
KEVIN: I'm sorry.
KATE: It's too late. Get upstairs. (Kevin walks up stairs and stops)
KEVIN: Everyone in this family hates me.
KATE: Then maybe you should ask Santa for a new family.
KEVIN: I don't want a new family. I don't want any family. Families suck!
He starts off with “everyone in this family hates me” not the other way around, and only gets the idea of wishing his family away when his mom suggests it.
The other possibility is that his perspective includes hating his family, I guess because of how they treat him. However, I have trouble seeing that he hated his family from the beginning, before they ganged up on him.
Also, if Kevin Changed from hating his family to wanting them back, that means he was influenced by the IC toward that change. But to me it doesn’t seem like it was the mom, or even anyone else in the movie, that influenced him to want his family back. Maybe the mom’s (or entire family’s) absence could have influenced it? I don’t know. To me, it seems like Kevin “grew up” over the course of the film, and grew into wanting his family back -- MC Growth, like @Gregolas suggests.