A completely clueless fool, in fact. As I wrote a while back, the episode was characterised by the Idiot Plot and Women are Wiser tropes. Daenerys doesn't escape criticism because she stopped to have a long chat with the masters while Meereen continued to be pounded into rubble. The Seven know how many civilians died.Jon is just an idiot as a commander. His army though smaller in size had a forest behind them. This would have negated all of Ramseys cavalry and pikemen and made the archers less effective. He did have the low ground which is always a bad thing but he also should have been aware of the grounds around the castle since its where he grew up! A poor commander indeed.