Hi there, I have 2 suggestions, one that I usually do myself after each upgrade and another that I haven't attempted yet but seems simple as well. This mod is so ridiculously useful and nearly bug-free that I've decided to nitpick just a little.
I don't use subsonic for podcasts and I do use playlists, so I typically change the podcast icon on the top to redirect to the playlist frame instead. It would be great to see (per user) customization icons in that top menu bar of subsonic, or possibly just a few more icons available and a bit of user specific css to hide the ones they don't use. I also replaced the file tree option with one which toggles the file view in lieu of the accordion, so I can get to my videos a few seconds faster, not sure what the actual file tree option is except to show new files, but I can't get to my videos through there.
I think the artist accordion on the left is amazing, especially with the genre selector, the only change I would have is to expand the letter when it is clicked from the alphabet on the top or bottom of the accordion. Currently those letters cause the accordion to scroll to the letter, then you must click within the accordion to expand the letter, a simple but convenient change hopefully. Wasn't sure if the accordion used in this mod is identical to the one posted in the mods section of this forum, so perhaps I should be asking its creator, let me know..
Hopefully some of this seems useful instead of coming off as a personal wish list.