I think a lot of UI changes are for the sake of change. The arguments I've heard for the recent font changes and some of the UI changes are a critical mass of r

I think a lot of UI changes are for the sake of change. The arguments I've heard for the recent font changes and some of the UI changes are a critical mass of retina screens. They've also added other screen/monitor tech like night-shift and true tone and have changed font smoothing. They're also slowing experimenting and merging macOS and iOS UI tooling, which necessitates a change on both parts. Personally, I also wish they would slow down or stop UI changes.