Well it may not be true for you but I have seen many people who have watched it just because it is a part of Dragon Ball franchise. And even though Naruto and Ft gets hated but you have to remember they didn't create a legacy like DBZ. DBZ made anime popular outside of Japan to tell the truth.So naturally there are many die hard fans for it who will watch it just because of it's name. Now looking back it doesn't seem anything special. If you read or see Tokyo Ghoul,Kingdom,Full Metal Alchemist,Hunter x Hunter,D Gray Man or Berserk or Monster Attack on Titan,you with find DBZ average.