From here on out, my phone would never enter deep sleep when connected to wifi. Any wifi hotspot - the ones I've been using, a hotspot I created from my desktop - the icon would show the phone constant receiving data via wifi. Using better battery stats, over about 5 hours on my desk, 4.5hrs were spent with a WLAN_RX_WAKE kernel wakelock with my phone sitting at 350MHz instead of deep sleep for that time.
I tried a bunch of different kernels (stock CM10, franco, imoseyon, etc) both new and old versions, but the problem was still there. I tried clean flashing a rom, and only installing better battery stats. Same thing with all kernels.
Factory restored google stock images to BOTH ICS and JB. I still have the problem. Tried disabling google location services. No dice. Tried a couple basebands, but I'm pretty sure that only affects cell/data performance, right?
I honestly have no idea what is going on. I've been on this hotspot (campus wifi) for months now without a problem, and now this. Some threads say that this is caused by DHCP requests from the router, but why would I have not seen this until now? My idle drain was at about 1-2% per hour before this, now it is close to 10-15%.