Sort to the top, or otherwise separate out casting "groups" vs. individual devices in the Connect to Device screen.
My home has about a dozen castable devices (Google ChromeCasts, minis, etc.). But 95% of the time, I want to cast to the groups I've created, like "Whole Apartment" or "Bedroom Speakers".
The current UI shows the castable devices in an arbitrary order, which means I have to hunt for Whole Apartment each time. It would be better if either frequently used devices, or just groups, we're sorted to the top of the list.