As with most programming on television, Discovery Channel's Shark Week is sensationalized to bring in viewers. It focuses on shark attacks and stories of shark attack survival more than actual facts about sharks. Additionally the programs are sub par at best in the sense that the writing and people involved are paid outrageous amounts of money to say whatever they are told.
Yes, Shark Week is overrated. It happens every year and there is only so much that people can learn about sharks. Why not have a different animal every year? I understand that people are fascinated by sharks because they kill other animals (and even people), but if Shark Week was not so commercialized and sensationalized, people would just be bored with it.