The only thing that really tempts me about the 4.2 is Miracast.

If you recall, I made a big rant about this feature many months back and how it is necessary on Android. Basically, utilize the Wifi n (dualbands even better) to stream the screen grab. Basically microHDMI feed without the cables.

A great idea for presentations, and perfect for home media/gaming setup.
Why?
It frees the microUSB port for HOST functions, and as these superphones are getting more powerful it won't be too long until the port runs a 5V current. That would mean many more accessories that "just work" without power.

They can even make a HDMI-dongle, one which simply passes the Miracast feed into a "dumb TV" port. It will also be inexpensive (<$50) unlike some AndroidSticks .

I don't know too much about gpu software, but any improvements to OGLES implementation and APIs is a boon not only for developers, but users and the whole platform. I just hope it gets there before Apple and Microsoft platforms get the traction they're looking for.