I have to say that in regards to Jared Leto as the Joker, I think he will do a fantastic job. I had some reservations about the recreating of the character where they added those stupid ass tattoos, but they are going to be largely covered anyhow so I can let that go. Jared Leto is going to do very well as a neurotic psychopath of a joker. He is definitely different from other Jokers we have seen in recent years, but try not to let that damage your idea of him.
The deaths of the majority of the freefolk army can be placed on Sansa as much as Jon. Moreso really, because while the pragmatic thing for Jon to do would be to let his brother die and not risk himself, but that would also betray his character. Sansa however withheld knowledge of the other, LARGER army that could have been planned around.