First up - thank you Peter!!
Like all changes, it might take a little getting used to and opinion might change with familiarity.
I know when the idea of additional song details being available in the sidebar list view was originally discussed, there was talk of maybe making which fields are displayed 'toggle-able'. I think this would be the ideal way forward - everything is On (visible) by default and then you can go and turn Off the fields you don't want to see in the list view.
Personally, even though I have tempo defined, I don't need to see it in the list.
I do want to see Key.
I don't need to see # of tracks BUT when doing song maintenance, it will be incredibly useful to turn this on so I can see at a glance which songs have less tracks (which in my case means the song is missing a guide vocal stem).
Then there is the freeform Notes field. That is an ideal place for guitarists to stick a Capo position and therefore would be great to have as an option.
Also agree that having the option to increase the font size of Artist field (has this got smaller to fit in the extra info?) and the 'Song details info' line would be nice. Although I think a lot of people will want to increase the font size (me included) and then reel it back when they realise that the row height for each song in the list view gets quite large, and thus you see less songs at any one time on the page.