This song just begs to be illustrated, doesn't it? I swear I get a new idea for a picture every time I look at it.
But then I feel that way about a lot of his songs, haha.
Looking back and forth between the two, I thiiiink the messiness is mostly an emphasis problem. Because I like the color scheme a lot. The painting could be a little neater in places like the knife handle, but it's not really distracting.
But the lineart version has a lot more contrast between heavy elements (birds, musicians, her dark hair) and light ones (the tracery, knives in her hair, negative space in the window), so there's an obvious path for my eye to follow around the composition. But when it's all colored, it seems like everything is jumping toward me at once, and I'm not sure where to look first. I think how I'd test that, if it were me, would be to take off the eye-catching red from the knives in her hair, and lighten the moon a few shades, and see if that helps. If it doesn't, the problem is probably something else an I don't know what I'm talking about, lol