• Skeletons can move as fast as the player even while drawing their bow back.
• Skeletons do not have their aim disrupted by player movement, nor from being struck and knocked back.
• Skeletons sometimes fire a bow at the player immediately after coming into line of sight, earlier than possible for a player to respond.
• Skeletons can backpedal at full speed while drawing and firing their bow.

These bugs enable skeletons to make combat maneuvers that are impossible for players to match, giving skeletons a strong advantage. This paired with their improved AI for 1.9, and high spawn rate, would make the game unreasonably difficult for newer players. I am a veteran player and am finding skeletons to be giving me a lot of trouble even as I am wearing well-enchanted armor and all other mobs have long since become trivial.