As far as I know, there still hasn't been a WWise template released for Attila. Modding music has been one of my favorite parts of the past Total War games and it's probably the most accessible way for new modders to break into modding the game.
It's something I think a lot of people overlook or don't think about when it comes to modding, but being able to mod the music can have a huge impact on the experience of the game. Personally, I get tired of hearing the same generic sounding tracks over and over. If only just for personal taste, it would be much nicer to create our own soundtracks.
Will there ever be a template released for Attila and Warhammer?