Regarding Music Explorer.
As said, I also love the layout, but I would go a little further, and this is what I would like:
For me, information about Top Tracks is not a priority. Yes, sometimes I use Track Rating, but never the Play Count. Of course I'm not saying it should be eliminated. I would prefer that this column was optional, that could be used, but not always shown, occupying a space that I would use otherwise.
I imagine the Music Explorer panel as an option to display all the information possible about an album that I have stored in their tags.
I use the right sidebar to show biography and images of the artist, and tracks lyrics.
But I need more

- I have defined custom tags for musicians (musician credits list), album credits (people Involved), and album producer, so I would love to see this information.
- Show the Album editor.
- Show the notes I've added to the album.
- Personal links related to reviews of the album.
In short, any tag that I've added to the album.
And where would this information be shown? Well, I see three options:
- That these tags were available for display in the right sidebar.
- Set the space occupied by the Track Rating as a panel similar to the right sidebar, with the ability to display any tag.
- My favorite: keep the right sidebar and add a new panel (something like the right main panel) and show between the two all the information.
I know it's too much, but these are my dreams. And dreams, perhaps ...