The deal with Leni Riefenstahl is much bigger than most people would care to admit.
Is your point that Cameron was very influenced by, and incorporates references to Riefenstahl, in his movies?
If that's it, it's not really a very important point.
Riefenstahl was an amazingly influential director. The entire direction of cinema was influenced greatly by her, as it was Georges Méliès or KKK-sympathetic D.W. Griffith.