Clearly the people who write the laws think that the landings are more important than the nav.
Well if you've done the IMCr you can navigate without being able to see anything out of the window, and as you appear to need instrument flying skills in order to fly in the dark it seems logical to me to do the IMCr before the night rating, so the nav isn't that big a deal. Being surprised at colliding with the runway when you thought you were still six feet up
is, it seems to me!
(From the viewpoint of having an IMCr, having done some of the lessons at night, but not having a night rating, because I don't fancy an engine failure at night.)