For phone security, you actually don't want root enabled by default, especially if it is being sold to noobs. Even for pro users, it is best to be able to do most of what you need to do on the phone without requiring root privileges. Although ofcourse if it is really your phone, you should have the ability to root it, which you will still be able to do provided you have an unlocked bootloader, or even just if can run an root program from over usb. It is much more important to have an unlocked bootloader than just having root access pre-installed.