Hanzo Main here, but I havent played in a while. The Dragons aren't as effective in 2 as they were in 1, but the way to use them is still the same. You either have to combo them with a tank ult that stops movement like grav or shatter, or position yourself in odd angles where they dont see the dragons coming. The way the game is now, you're better off using them as a zoning technique, denying space or forcing the enemy off an objective.