I'm also having the same problem. I have a US global model XT-1032 Moto G. No matter what the heck I try to do the radio always stays off on the phone. It worked fine prior to the 4.4.2 OTA update.
I've tried flashing just the modem from the 4.4.2 and 4.3 US firmwares for both the XT-1032 and XT-1034 versions and neither of them work, it always shows the network as unknown and the radio being turned off.
I have even tried erasing the modemst2 then modemst1 in that order and then flashing the modem with the non-hlos.bin file hoping that if I did it in reverse to the normal order it would fix the issue.
The sad thing is that since I unlocked the damn bootloader to do this, now I can't get any kind of warranty repair done on it by Motorola.
UPDATE: the Retail US 4.4.3 factory image from here Blur_Version.210.12.32.falcon_umts.AWSRetail.en.US fixed the radio on my XT-1034 so no need to use the previous method if you are having the same issue, just try flashing that version on your XT-1034