Ok, I went ahead and set up a full view to do this. It's sort of medium complicated. It requires a smartlist and then a view that builds on the smartlist. Here's sort of a step by step summary of how to create it:
1. Make a new smartlist. I called mine "Artist Genre List". Here's the definition of the list that you can paste into the Import/Export area:
[Media Type]=[Audio] ~limit=-1,1,[Artist],[Genre] ~sort=[Artist]
You should now see a list of artists and each genre the artist belongs to. It will be one line (song) per artist/genre pair. The song is random and will change if you refresh the list. That's ok; it doesn't matter.
2. Make a new view. I called mine "Artist Genre Maint". A panes view is probably best. Go to Customize View > Settings > Included Files > set rules for file display. In the Import/Export box, paste in this definition:
[Media Type]=[Audio] playlistid==1070328854 [=save(0,v_genres[Artist])1]=1 [=save(math(1+load(v_genres[Artist])),v_genres[Artist])1]=1 ~sort=[Artist],[Album Artist (auto)],[Album],[Disc #],[Track #],[Name]
That big number for playlistid is unique to my system. Once you cut and paste and click ok, you'll see a "Playlist is any" line with a blank playlist. Click on the blank box and find the name of your playlist and select it. That will internally fill in the unique ID from your system for your list. Then it will work.
3. In this view, set group by to None.
4. Make a new expression column. I called mine "Genre Count". Paste this in as the expression:
load(v_genres[Artist])
5. Click some columns to sort correctly. Click in this order: Artist, then Genre Count. You'll need to click Genre Count twice to make it sort with the highest count at the top.
Now, unfortunately, this is just a nicely sorted list. You can't actually change the Genres from here because it will only contain one song per Artist/Genre pair. So, I'd recommend that you open another tab, or another split view with an Artist list in a Panes view. Then, when you find that (for example) Blues Traveler has 3 different genres, you can switch over to the Artist Panes, change the Genres for all of the songs there, then switch back to Artist Genre Maint and continue. The sorting in Artist Genre Maint doesn't seem to "stick", so you'll have to resort it each time you change Genres in another tab. A small price to pay for such convenience!
Can someone try this out and see if I've described this correctly and used the correct definitions for all of the various lists and things? I'd appreciate it.
Brian.