I have actually put some thought to it and here's my take.
Ideally the Album Art shouldn't have an overlay with information that is already offered BY the album art.
On the other hand, not all songs have an album art (and IIRC Poweramp still doesn't auto-search for missing album art).
So my take is this: First of all, forget the boxes.
If you HAVE to have text overlaid on top of an image, go subtitles style. That is, white text with a THIN black outline (could also be colored as per the background). That would be a lot less distracting than now.
However ideally I would also prefer the option to completely HIDE overlays with information that the album art already offers.
The proper way to do this programmatically would mean that Max should first have to check if there is indeed an album art and then decide whether to show the overlay, but a quick-and-dirty approach to this would be to simply change the ORDER that Max overlays the various objects.
Specifically, if the album art is overlaid last and OVER the text overlays then the text is still there but invisible. In songs with no album art the text overlays are overlaid last and thus visible.
EDIT: I forgot to clarify that the above are for the Playback screen, the grid view library list is jsut great the way it is!
Lastly, the Song title (which obviously isn't mentioned in the album art) could appear bellow it or where the metadata currently are.