The advantage of bottom aligning album artwork on the 16:9 display is that none of it is obscured by the name of the song, and even when you double-click the Home button to bring up the music controls, very little is obscured.I'm sure Apple went through every permutation of this and came up with the best compromise they could, but as a mental exercise it's interesting to explore what the other options might be.Included in that is the album art for your playlists.While not an option ingrained in the mobile app itself, changing a playlist's cover image on your phone can still be done.
Worse, there's a big black gap between the top of the album art and the bottom of the time bar.
Unfortunately, this trick is only available to i Phone users right now, as the Android version of Spotify doesn't allow you to edit playlists beyond a simple name change.
If you're on Android, you could use an app like "Change playlist image - Spotify" to do so, if you don't mind signing in through a third party.
Because of the 3:2 aspect ratio of previous i Phone and i Pod touch devices, however, and because the top of the album art and the reflection beneath it peak through the translucent time and slide-to-unlock bars, the visual weighting was close enough to appear centered and thus, balanced.
Not so with the i Phone 5 and its 16:9 aspect ratio.
Next, select "Add to Playlist," then choose the playlist you want to change the picture for or select "New Playlist" to create one from scratch.