+1
An option to select if you want to show Artists:Artist or/and Artist:Perfomers would be great.
You could use the Additional Tagging Tools plugin from the add-ons section to copy Artists: Artist and Artists: Guest Artist or Artist (Displayed) to a custom tag and then display by the custom tag.
I've tried with this, and works, but with a custom tag there's no artist picture (just album cover).
Or for something that is continuous, a virtual tag that just pulls the first artist from the list of artists and display by that virtual tag. Come to think of it, that's probably the better option.
This is the option that I'm using from long ago (with the Album Artist tag), but is not perfect.
I give an example: In the Album "Duke Ellington & John Coltrane" there's two main Album Artist, so I've tagged it this way (Duke Ellington; John Coltrane in the Album Artist tag).
When you filter the thumbnail browser by letter D, the Album is shown twice, one for Duke Ellington and one for John Coltrane. The same with letter J.
I've tried too with the Artist tag, with the same behaivour.
Hence, besides my +1 for the initial wish, I think that the thumbnail browser need it's own AZ jump bar to work better.