> The final major downside is having to switch apps out of navigation to control music then switch back,

But... you don't. Tapping on the home button once more or swiping to the right on the app page reveals the home screen which has navigation and music together:

https://devimages-cdn.apple.com/wwdc-services/images/D35E0E8...

https://cdn.mos.cms.futurecdn.net/wgH6RZrtKkuAQkJUjfWW8V.jpg

It even adapts to vertical screens:

https://i.redd.it/n7e0st8ebyh81.jpg