i had the same issue however it was succesfull on first boot, this method didnt work for me on 4.3 and had to use the modified recovery method, anyways this time i flashed pauls stock 4.3 retail did the ota to 4.4.2 and tried the superboot and it worked
1. The device has just been released and yes relocking bootloader will leave traces behind... but I am pretty confident that sooner or later we will be able to lock it without leaving traces behind.... someone always finds a way.
2. Ive rooted successfully 2 moto g using 2nd method, it works if you follow the instructions properly and i had a few problems on the way but were easily fixed (usb driver issue).
3. I had this issue when I switched my phone in for the first time and tried to install apks from sdcarf, paul also confirms hes had this problem on a non rooted phone. Factory reset solved the problem.
Personally I wouldnt buy an android device and not root it, all ny devices are rooted :D
If your on windows 7 go to device manager, you will see something in other devices with no driver installed, just right click on it and go to update driver software, it gives an option to search automatically or to browse on your computer, click on the second option , if you have already installed the motorola usb drivers then go to the bit where it says "Let me pick from a list of device drivers on my computer" search for motorola and select either composite adb drivers or mot single adb drivers, both will work :)
Thats no error, that suppose to happen, just select recovery from the bootloader list and press volume up and not the power key, it shud boot into recovery.
Ive had that message on 2 moto g and have successfully rooted both just need to follow the instructions on op
Thanks I have 2 drivers, mot composite adb interface, mot single adb interface. Which did u go 4?
Edit. I went for MOT SINGLE ADB INTERFACE and its worked, finally rooted on both, strange what happened.
Edit2 looks like both options work, I did adb devices to check if device was attached and it showed up.