The main thing missing compared to the 3.x version that would hinder the flying archer strategy is its regeneration and needing to use Wish or Miracle to keep it dead. Trolls and Vampires have conditional regeneration, Zombies have Undead Fortitude that gives them a chance not to die when reduced to 0 HP, the concepts were there they just chose not to implement them.
The main thing missing compared to the 3.x version that would hinder the flying archer strategy is its regeneration and needing to use Wish or Miracle to keep it dead. Trolls and Vampires have conditional regeneration, Zombies have Undead Fortitude that gives them a chance not to die when reduced to 0 HP, the concepts were there they just chose not to implement them.