That was quick. I think this is a major improvement over the blank sides. I think it would have a better effect once the artist image is extended down as you mentioned. Additionally, maybe if the album covers were softened by the dominant color from the artist picture, it would look more uniform.
For later on, if this works out for all, I suppose that one would also like to see relevant images in the background, so that it not only looks good but is relevant... one may notice an artist image that they had not played in a while or something like that.
They are not lazy... just more efficient.