When I was reading this post of his, I immediately thought of the Location History (Location reporting) being the issue here, he may have explained this already but with the amount of posts on this thread is not easy to follow everybody, so spasell, do you have Location History on? You can still use Google Now but until Google changes back to separate Location reporting from Location History I'd always recommend to turn Location History off.
If you have Location History on, look no further, this is your battery drainer, it pings your phone every few minutes, every time it detects a different location, you can still use Google app, just turn your Location to Power saving Mode (Wifi and cell signal) and just use High accuracy when you need to use Google maps or any other similar app, you will see that you won't notice any difference with location on or off when in power saving mode. Plus you can still use Location services on google Maps, the one that tells you the nearest places and stuff.