It's not so much the composition/styling that bothers me, it's Lily's own proportions... Her face looks really small compared to her upper body (those shoulders!!) her hand looks big and her arms look weird... But as I said I love Lily and i'm glad she got the cover
ETA: I've just looked at the cover again, hiding her arms with my thumbs, and it looks amazing... So my real problem is the arms...
They have purposefully put a lot of light on her lily white arms - to enhance the weird pose - personally I love this kind of 80s power pose, especially when combined with a face that is wholly different from the kind of face/hair that would go with the shoulders in a real 80s shot - the face is more new wave than you'd ever see in the mid-80s wholesome shots.