However, I didn't find No Crystal Stair boring at all. But you are right--kids would, for sure. Too many voices, too many temporal shifts, too many anecdotes that might seem like they aren't adding up to something. But I really think that they are. Which is why I think it would have to be taught.
If the most (only?) interesting part of a book is the premise, and that premise is poorly dealt with throughout the novel, I would suggest that the novel is not just deeply flawed, but craptacular.
I have not been paying attention to grammar.