-nw is separate option. -nw is not combination of -n and -w, so don't worry that -nw will 'not configure any interfaces.' I think -nw is exactly what you want, i.e. force dhclient to become daemon immediately (not wait before getting the address). I don't think it's necessary to be it the default behavior. If you want it, use '-nw' option.
Yeah if -nw option will not effect test result, I think this should be ok. Feel free to close it with notabug.