I love the option to change to "dark mode" in the System Preferences, and it's a pretty easy few clicks to do it, but what I'd like to see is a faster click to it, or option of it being totally automatic too.
On the first part, maybe just making the option immediately switchable from the left Apple menu or somewhere else in the Finder's menu system, available easily and by one pull down and click?
On the issue of automatic, something similar to the Dynamic Desktop picture change, or like with Night Shift; able to be scheduled on the time of day. Or even better, make this an option to auto enable or disable, as with the iOS devices that use True Tone to modify the color - how about the same thing for Macs, based on the ambient light levels from the computer's sensor.
Just my two cents on that...
tell application "System Events" to tell appearance preferences to set dark mode to not dark mode
Use any number of different methods to assign a schedule / key combo / etc. You could even add it to the touch bar as an automator workflow...