Explore the feasibility to move all real models to a not UI thread. Replace the models in the UI by proxy models.
After that, try to have a generic view that can display both all albums and all artists views.
After that, try to have a generic view that can display both one album and all tracks views.
This is necessary to allow the user to customize the kind of views he has. That should allow to match the "Simple by default, powerful when needed".