Android Police collected all the issues with 4.2- must read for Nexus owners
I have noticed the slow charging/faster battery depletion thing myself. It is maddening. I left it at 60% before I want to sleep and when i woke up in the morning it was at 40%, where in the past it would be at around 58% or something. It also charges TOO slowly at times.
I also noticed the lack of butteryness.
I never use Bluetooth so I don't really care about that. And Google Now is definitely not as broken on my N7 as is suggested in the comments. It works just fine, actually.
I also had one random reboot and some apps are crashing more often with some others not working at all. I can forgive that since it's a new release and devs must update their apps.
Lockscreen widgets work just fine for me.
And yeah, December is missing. :D
So what's your list?