The main flaw is Zemeckis' direction. In light of the film's trope that time is an anthropocentric construct which space recognizes randomly, Zemeckis cannot leave his logo-centric post. Zemeckis cannot help but show us what Hanks sees. He cannot refrain from the close-ups of Hanks. He will not allow the camera its own narrative.
Every shot is more concerned with the details and Hanks than the picture itself.