I'm having the same issues that I have read over and over on the web and on this forum. Slow battery charging, battery drain, slowness of all apps including text messaging and email. I'm also having phone signal issues and wifi issues, causing text sending to hang for long periods.
But I have one more problem that appeared almost immediately after the upgrade. That is... a scareware nagbox popping up intermittently and often. It is called clickgo.mobi and warns me that I have to upgrade my android version-which I clearly don't want to click OK to! It is not only occuring when I google or browse the internet. It is definitely on the phone. It pops up while I'm texting, or really any old time. And I had not installed any new apps. Just the upgrade to 5.0.2.
So... I installed another adware program to try to rid the phone of it. It detected nothing. I deleted some suspicious looking folders and did a restart. It seemed to be gone. But after reading your fix for the performance issues, I decided to boot it in safe mode to see if it really was a 3rd party app causing the problem. In safe mode, what do you think was the first dang thing that popped up when I swiped to unlock the phone? That's right. clickgo.mobi says I need to upgrade my android because it is not up to date.
Seems it really is embedded, as I suspected, in the operating system that was downloaded from vzn to my phone. My understanding is it would not otherwise be able to run in safe mode.