The idea of the Nest systems (in a very distant way) was good. Nest itself won't be able to deliver. However, the idea Nest used to push itself wasn't a new one. It's something that's been repeating for years, that existed on display in movies, and that many (who are rich enough) already have (fully automated and "cool" home systems).
Also, the way they are implementing all of these things seem brute force, crude, and bulky. The house is a finite space filled with a specific set of things. Linking them all together (and to a central control) and having them all work together automatically seems like a very straightforward thing. So much so that many hobbyist Engineers already have their home systems working that way (and in a much more elegant and scalable way than the crap being pushed).
The only thing I'm really excited about are the LED light bulbs. Not the wireless control and programmable nature of them (though that's cool), but the range of color temperatures and intensities they make available and then the fact that they can programmatically be controlled/changed/accessed.
That is, it's cool to me to be able to buy a light bulb, then be able to link it with a clock and light sensor, then have it automatically adjust the intensity and color temperature of its output throughout the day as necessary.
But then LED light bulbs (programmable in that way, even) have been around for years.