I don't know, Maybe the gradient on left side of the image (when it's right-aligned) needs to be even wider. Now it works very good with some images, but with others it's still a bit odd. Adding more gradient may be bad for the images that now look good, but good for the ones that look bad. I think it needs more testing and more opinions from other users.
About the change in alignment when you press the right panel button...
The change in alignment is not a problem as long as it's not inmediate when you press the button to open/close the panel – just change it on the next image (on previous versions it worked this way)
I still think this should be considered. Of course that would cause a problem: if the rotation is paused, the alignment would never change. More users should give their opinion, but if Steven is tired of working on this, an alternative to all the problems would be aligning always to the left.
BTW Steven, please fix the vertical margin between the controls and the album cover (on small and medium cover sizes) to be the same as the left margin.