I can't really answer your question because I've never actually stayed there, however I am considering for next winter and emailed the hotel as well regarding upgrading a room booked with points. I got the same rates you did and when asked the difference between the two rooms, I was told that both have full harbor views, but Superior room size is ~350 sq ft and Deluxe is ~450 sq ft. I was also disappointed in this upcharge because cash differences are not as high.

Also having already been to HKG and seeing the location of this hotel its hard for me to believe that this hotel can have a bad harbor view room. All the rooms facing the harbor should have a great unobstructed view because this hotel sits right on the water edge.