"Silent Night" is a simple song. That's what makes it so very moving: simple does not mean empty or shallow. It is like "What Child Is This?," beautfiul and simple but not plain.
That simplicity may be why so many singers choose to add all sort of flourishes when they record it. I am going through iTunes looking with little success for a version that is simply sung, in the spirit of a song written for voice and guitar (because the organ was broken), not for trumpets and strings.
It is a song of quiet wonder, not glory and majesty.
That should be saved for the "Hallelujah Chorus, " or at least "Angels We Have Heard on High."