Please add visualizer functionality and controller layout customization.
As a Port and Connect (S2 compatible) owner who integrates into other amp/passive speaker zones, it would be great if these features were available.
For example, I have a Sonos zone in my primary home theater by way of Port, but use my Mac Mini to display the Sonos app on my TV. This works, but it could be a lot more visually appealing if there was a way to customize the layout. For example, larger cover art, bitrate/resolution, etc. This is not an edge case.
Take it a step further and add some eye candy with options for visualizers. Heck, open it up to the community and I bet we'd see some awesome content brought forward. VU Meters would be cool for example. Lot of possibilities. People (not all) want the eye candy and your competitors are incorporating it alongside support for lossless high resolution audio. If you're not going to support the latter, you should look to support the former in my opinion.