You cannot compare this december tour with the two performances in 1973.....just take a look at the circumstances in 1973; a show before the eye of the world! I really like the two shows in 1973, but when it comes to enthousiasm and most of all a relaxed and loose Elvis, the Pittsburgh show is much much much better than the Aloha shows.
During both Aloha shows his voice was a bit weak and you can see the tension (or is it him focussing...).
In december 1976, Elvis was in very good mood, with some great surprises (Rags to Riches man!!!!). Too bad it was just a last glimpse of him really enjoying what he was doing, and doing this at 200% (together with some highlights in 1977 ofcourse...).