I'd love to see a complete thermostat programming interface, with saved schedules.
For example, a "normal" schedule, a "guest" schedule (use more energy, but be a gracious host by keeping our guests more comfortable), a "vacation" schedule (use less energy, but keep the pipes from freezing), etc.
What I have in mind is a simple interface for programming a schedule (2 or 4 time set points, heat and cool temps for each day (set multiple days at once, of course)). Then save the result and give it a name. Then "upload" any saved schedule to the thermostat to make it active.
This was a feature I used once and really liked.