Personally, I would voice that I would prefer the spectrum visualizer to either be (a) the same the same colour as the rest of the fill area, OR (b)that it be incorporated into a taller playbar and have the playbar background.
The good thing with (a) is that the color changes depends on the artist picture, and no matter the skin, there won't be any conflict regarding visibility.
(b) Runs the risk of the skin conflicting with a color chosen by the artist picture... so this would mean that moving it to the playbar would then require removing the spectrum bar color changing feature, unless you can override possible conflicts.
Therefore, the skin makers would determine the color of the spectrum visualizer.
Doing (b), I think would also require the removal of the top skinner bar, so the image looks more free above the playbar, as if they are emerging from the player. Not trapped between two bars.
Regarding navigating the playlist:
I personally have no problems with it (But I may not be the best judge since I am so accustomed to theatermode), but it may not be a bad idea to have the now-playing assistant as an option when one right-clicks on the artist picture area, instead of just 'customize panel settings'. (I know it is also available from the top bar and the bottom)
They are not lazy... just more efficient.