I just spent some time watching it. I have only good thoughts about it. Your flying, scene length, compositions, editing, color grading, music track, and interesting subjects were all building blocks of what I think we all strive for when we go out to film. I've been to Sydney and your harbor view of the skyline and opera house were fine. The recordings of the surfers paddling out, meeting the waves, and scenes of the beaches and surf from above were perfect. And you were really fortunate to capture that whale mom and pup! That would have really made my day! Your Point of Interest circle of the lighthouse was as good as anyone's.
I think the film was sometimes repetitive with the surfers and swimmers but it could easily be shortened.
I think some of the criticisms were uncalled for, and one was just plain mean-spirited.
I have never aspired to be a You Tube star, or to make a penny from You Tube, or have the highest viewership. Your goals might be different. I have stopped submitting to You Tube several years ago because I think the audience is not sophisticated enough, like the forum guys are. I now only submit to Vimeo. I film for my own hobby and pleasure, and to create mementos for myself and my family and friends. I am please when I get good commentary and I know, above all, if the product is good or not without being told by others.
Just ignore some of these critiques and keep working on your skills, flying moves, and technique. Don't fret and worry about these "film critics...they certainly are no John Houstons or De Milles.
Dale