In musical form it truly is a "Rhapsody." And it's "Blue." Recorded jazz wasn't even ten years old when it was recorded, and barely a recognized form any longer if that among most music listeners. It had novel elements and was written to be popular and catchy. Looking at it through eyes one hundred years older . . . yeah it doesn't look the same as it did then or even sixty years ago.
I like it, a lot. I get that others don't. I don't share Iverson's view of it.