2. Wrong Positioning
Jon Snow is famous for knowing nothing but after being saved by Sansa in the Battle of the Bastards, you’d imagine that he’d learn to draw up a decent battle plan. His schemes against the White Walkers was filled with shortcomings, but the most major mistake was probably placing the Unsullied and Dothraki on the correlative side of the army’s fiery troughs and the safeguarding of Winterfell’s walls on the diverging. Honestly, lighting the destructive flames instantly and allowing the armies to gather wights as they clambered through the fires would have been a more fruitful plan.