+ 1 for variables. It would be nice to persist state somewhere other than on a physical device. Even if it was as primitive as a fake device with an on/off state. I like to have a current state for my house, e.g. Morning, Day, Evening, Sleep, Vacation, Emergency. I can use the state in programs to determine how the response to certain actions should proceed.
As far as a case statement, any ability to have nested IFs or Else Ifs would work. Else Ifs would also work in your GUI.