DC characters seem pretty overpowered without huge character flaws. To me, they seem almost like caricatures of power where they don't really have human flaws but silly external flaws (like Superman's kryptonite or Martian Manhunter's fear of fire). I thought the Avengers worked because of the flaws or quirks in the characters that made them more human or accessible and it also gave light to their vulnerabilities (apart from Thor, he just seemed strong and immortal and could probably defend earth on his own, given enough time and battle tactics education).