1. You’ve buried every relevant action multiple clicks into the UI. Simple things like adding a min-height or changing the responsiveness are now much harder. The UI is tanking designer productivity.
2. There’s no hierarchy in the new UI. Scannability is out the window. Sitting here squinting at low-contrast UIs with size 10-pt font like the old geezer I apparently am.
3. You’ve moved multiple properties. Why? This increases the mouse distance that you have to travel to do basic tasks.
4. Even as someone who’s done print, I’m baffled why you chose color swatches as the icon for theme variables. The icon choices in the new UI reminded me of VSCO with how obtuse and unclear they are.

I’m shocked that a tool for designers with a reputation for a user-centered culture not only shipped this UI, but then forced it on its users.