I believe they got rid of health bars because it was always some overlay that takes a away some of the "realism" of the game. So they wanted the player to just see the game and nothing else. The player cannot see his health, but he can´t die in one shot, so they implemented some overlay for making it visible that you are "weak" and have to hide somewhere. To regenerate your health, that is. I never liked it, i want my hearts from Zelda, everywhere.